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. The only kind of gag worth pulling, I always maintained, was a cosmic one—till I learned the 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. had anesthetized all the experimental mutants, and the metabolic nothing around that might connect the sudden appearance of the volplas volplas only a few more weeks to learn their means of survival and My son asked, "What happened to the animals?" "Turned them over to the university for further study," I lied. "Well," he said to her, "you can't say our pop isn't a man of decision." Twenty-four hours later, there wasn't a sign of animal experimentation 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, his graying head from a cage. I had called them volplas since the day withdrew the intravenous needles from my first volplas. I carried their limp little forms out to a mattress in the lab, two girls and a boy. 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. structures. They were lovely, perfect little creatures. My wife tried the door, too, but more subtly, as if casually touching the knob while calling. "Lunch, dear." She peeked too, as she had for fifteen years, but I blocked her view when I slipped out. "Come on, you old hermit. I have a buffet on the terrace." The maid beat it into the house. I flipped a hamburger and a slice of onion onto a plate and picked up the ketchup and said, "I've reached the dangerous age." "Oh, good heavens!" I dowsed ketchup over the hamburger, threw the onion on and closed it. Pacific shimmered. I thought, "All this and three volplas, too." brought me a bowl of salad and I munched the hamburger and watched the boy unsaddle the horse and slap it away to the pasture. I thought, "By God, wouldn't he have a fit if he knew what I have back Mother . Why?" "Because, dear, I said so." The boy had already raced across the terrace and jack-knifed into the "Well, if you feel that way about it, they'll both have to start wearing clothes." I gulped the last of my hamburger and washed it down with the beer. "This place is going to hell," I complained. "The old man isn't allowed to pinch the maid and the kids can't go naked." I leaned toward her and smacked her cheek. "But the food and the old woman are still the best." "Say, what goes with you? You've been grinning like a happy ape ever found a litter of flat stones that had young black-snakes under each slab. I filled a pail with them and took them into town and dumped them on the walk in front of the movie just as Theda Bara's matinee let out. ?" I grinned. "Forgive me if I eat and run, dear. Something in the lab can't wait." The fact was that I had something more in the lab than I had bargained 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 growth in the metabolic accelerator. When I returned to the lab, they his arms out and tried to tease the spars open. They were not new. The spars had been common to the basic colony for years and were the result Suddenly, as I teased the male volpla, this happened. It was a true gliding plane, perhaps even a soaring one. I felt a thrill run along my back. 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 decidedly amorous. I danced into the kitchen table and tipped over a basket of green corn. The maid promptly left the kitchen for some other place. 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. loose. There would be volpla colonies all up and down the Coast before anyone suspected. One day, somebody would see a volpla. The newspapers intelligently." The government would issue denials. Reporters would "expose the truth" 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 my volplas. But only for a moment. I used the metabolic accelerator to cut the volplas' gestation down to one week. Then I used it to bring the infants to maturity in one month. By the next spring, I had a colony of over a hundred volplas and I shut 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 Until I had them out in the open country, it had been impossible to whoop. After that, it was a carnival. They learned quickly and brilliantly. They were not fliers Of course, the volplas didn't want to return to the lab. There was a each other. Then they got out and lay on their backs with the planes stretched to dry. I watched them affectionately and wondered about the advisability of 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 across the stream and landed in an oak on the opposite hillside. I pointed. "There's your food, if you can kill it." He looked at me. "How?" "I don't think you can get at them in the tree. You'll have to soar up silhouette of the volpla marred the sky so near. I looked back, as did the girl remaining beside me. The soaring volpla swiftly beating wings. I saw one of the male volpla's planes open a The doves separated and began to zigzag down the valley. The volpla did plummeted to a hillside. The volpla landed gently atop the hill and The volpla beside me danced up and down shrieking in a language all her 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 eat this?" I laughed and took his tiny, four-fingered hand. In a sandy spot them. This was another marvel, but first I wanted to teach them how to clean the bird. I showed them how to spit it and turn it over their fire. Later, I shared a small piece of the meat in their feast. They were gleeful and greasily amorous during the meal. When I had to leave, it was dark. I warned them to stand watches, keep the fire burning low and take to the tree above if anything approached.

<question>:
How were the Volpla able to eat solid food so quickly?

<options>:
A Their anatomy is not human, and their more developed digestive system handles solid food much earlier
B They mature very quickly, as a result of their mutant status, so it would be easy to eat anything
C Their growth had been artificially sped up, so they passed the stages where they would have needed different food
D Solid food was the only thing they were offered, so they learned to eat it

<answer>:

C