Read the following passage and questions, then choose the right answer from options, the answer should be one of A, B, C, D.

<passage>:
Volpla That next week, I transported all of the volplas out to the oak woods. There were a hundred and seven men, women and children. With no design on my part, they tended to segregate into groups consisting of four to eight couples together with the current children of the women. Within these groups, the adults were promiscuous, but apparently not outside the group. The group thus had the appearance of a super-family and the males indulged and cared for all the children without reference to sent an academic zoologist into hysterics lay there in the metabolic the volplas to use the fire drill and they were already utilizing the local grasses, vines and brush to build marvelously contrived tree houses in which the young, and sometimes the adults, slept through midday and midnight. nothing around that might connect the sudden appearance of the volplas with my property. It was already apparent that it would take the volplas only a few more weeks to learn their means of survival and about the disemboweled buildings and she said, "What on Earth is going on here?" "Well, Dad-dee, I can't!" "What?" "You can't turn this old key tightly enough." Except, of course, that the woods were full of volplas. At night, I Volplas at last. Three of them. Yet I had always been so sure I could create them that I had been calling them volplas for ten years. No, through the dark overhead, they chattered and laughed and sometimes his graying head from a cage. I had called them volplas since the day moaned in winged love. One night a flight of them soared slowly across old Nijinsky's elongated arms and his cousin's lateral skin folds had the clamp. could hear them faintly when I sat out on the terrace. As they passed ?" "Do you understand the word?" "No." rodent faces. At the door to the outside, she turned perilously and withdrew the intravenous needles from my first volplas. I carried their The accelerator had forced them almost to adulthood in less than a month. It would be several hours before they would begin to move, to learn to feed and play, perhaps to learn to fly. Meanwhile, it was clear that here was no war of dominant mutations. Modulating alleles had smoothed the freakish into a beautiful pattern. "Come on, you old hermit. I have a buffet on the terrace." Pacific shimmered. I thought, "All this and three volplas, too." I thought, "By God, wouldn't he have a fit if he knew what I have back there in that lab! Wouldn't they all!" "Because, dear, I said so." The boy had already raced across the terrace and jack-knifed into the "Oh, not that again! You were dangerous at any age." my first volplas were shockingly humanoid. They were also much faster than had been their predecessors in organizing their nervous activity after the slumbrous explosion of Suddenly, as I teased the male volpla, this happened. By four o'clock that afternoon, I was feeding them solid food and, with the spars closed, they were holding little cups and drinking water from them in a most humanlike way. They were active, curious, playful and He said, "'Ello, 'ello." The maid promptly left the kitchen for some other place. golden evening slant across the beautiful hills of our ranch. I dreamed. I would invent a euphonious set of words to match the Basic English vocabulary and teach it to them as their language. They would have their own crafts and live in small tree houses. I would teach them legends: that they had come from the stars, that loose. There would be volpla colonies all up and down the Coast before anyone suspected. One day, somebody would see a volpla. The newspapers would laugh. Then someone authoritative would find a colony and observe them. He would conclude, "I am convinced that they have a language and speak it intelligently." The government would issue denials. Reporters would "expose the truth" and ask, "Where have these aliens come from?" The government would reluctantly admit the facts. Linguists would observe at close quarters and learn the simple volpla language. Then would come the legends. Volpla wisdom would become a cult—and of all forms of comedy, cults, I think, are the funniest. "Darling, are you listening to me?" my wife asked with impatient my volplas. But only for a moment. I used the metabolic accelerator to cut the volplas' gestation down to infants were females, which sped things up considerably. By the next spring, I had a colony of over a hundred volplas and I shut down the accelerator. From now on, they could have babies in their own way. I had devised the language for them, using Basic English as my model, and during the months while every female was busy in the metabolic accelerator, I taught the language to the males. They spoke it softly in high voices and the eight hundred words didn't seem to tax their little skulls a bit. My wife and the kids went down to Santa Barbara for a week and I took the opportunity to slip the oldest of the males and his two females out I put them in the jeep beside me and drove to a secluded little valley about a mile back in the ranch. They were all three wide-eyed at the world and jabbered continuously. They kept me busy relating their words for "tree," "rock," "sky" to the objects. They had a little trouble with "sky." Until I had them out in the open country, it had been impossible to appreciate fully what lovely little creatures they were. They blended Almost two hours went by before the male made it into the air. His playful curiosity about the world had been abandoned momentarily and he was chasing one of the girls. As usual, she was anxious to be caught The two girls reached him before I did and stroked and fussed over him so that I could not get near. Suddenly he laughed with a shrill little whoop. After that, it was a carnival. They learned quickly and brilliantly. They were not fliers they were gliders and soarers. Before long, they took agilely to the trees and Of course, the volplas didn't want to return to the lab. There was a leaving them out here. Well, it had to be done sometime. Nothing I could tell them about surviving would help them as much as a little naturally have forgotten the ways of living outdoors." "We can learn again. We want to stay here." His little face was so He looked around slowly at the breeze playing in the branches and they leave while you are climbing." himself, streaked down-valley a way and caught a warm updraft on a silhouette of the volpla marred the sky so near. I looked back, as did the girl remaining beside me. The soaring volpla The doves abruptly gave up their hard climbing and fell away with swiftly beating wings. I saw one of the male volpla's planes open a little. He veered giddily in the new direction and again dropped like a The doves separated and began to zigzag down the valley. The volpla did lower than the bird he was after, then swept up and intercepted the plummeted to a hillside. The volpla landed gently atop the hill and stood looking back at us. The volpla beside me danced up and down shrieking in a language all her It was a hero's welcome. He had to walk back, of course—he had no They were raptly curious about the bird. They poked at it, marveled at its feathers and danced about it in an embryonic rite of the hunt. But When I had to leave, it was dark. I warned them to stand watches, keep The male walked a little away with me when I left the fire. I realized I had blundered by passing him an English name. "In your language, Pohtah."

<question>:
Why was the Volpla vocabulary limited when the narrator took a few into the valley?

<options>:
A They had not been alive long enough to learn enough English to communicate well
B They were encountering concepts that were unfamiliar from the lab environment
C They are not smart enough to have a fully developed language, no matter how hard they try
D They were confusing their own language with English, having trouble keeping the languages separate

<answer>:

B