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

<passage>:
Sound and movement below. Mom flicking off the controls of the Dad's deep, happy voice echoed up the stairway: "Hi, beautiful!" Please, Mama , his mind cried, please don't tell Daddy what I did. There was a droning, indistinct murmur. Dad burst, "He was doing what ?" Why did you tell him, Mama? Why did you have to tell him? humming movement under his weight. To his left, on the wall, he caught kaleidoscopic glimpses of Mom's old like a wounded bird falling out of the sky. He saw that Dad and Mom were waiting for him. Mom's round blue eyes were full of mist and sadness. She hadn't bothered to smooth her clipped, creamy-brown hair as she always did when Dad was coming home. And Dad, handsome in his night-black, skin-tight Pentagon uniform, had become a hostile stranger with narrowed eyes of black fire. "Is it true, Ronnie?" asked Dad. "Were you really—really reading a book?" Ronnie gulped. He nodded. held Ronnie's arms and looked hard into his eyes. For an instant he became the kind, understanding father that Ronnie knew. "Tell me all about it, son. Where did you get the book? Who taught you to read?" Ronnie tried to keep his legs from shaking. "It was—Daddy, you won't make trouble, will you?" boy's no good. His father never had a job in his life. Nobody'd even offer him a job. Why, the whole town knows he's a Reader!" Mom stepped forward. "David, you promised you'd be sensible about this. You promised you wouldn't get angry." Dad grunted. "All right, son. Go ahead." shack ? You actually—" "Dear," said Mom. "You promised." A moment of silence. Ronnie's voice quavered. "Go on," said Dad sternly. "And I—and Mr. Davis said he'd teach me to read them if I promised not to tell anybody. So he taught me a little every day after school—oh, Dad, books are fun to read. They tell you things you can't see on the video or hear on the tapes." "How long ago did all this start? Dad rose, fists clenched, staring strangely at nothing. house in Washington instead of trying to commute." "David," said Mom, very seriously, almost as if she were praying, "it won't be necessary to have him memory-washed, will it?" Dad looked at Mom, frowning. Then he gazed at Ronnie. His soft-spoken words were as ominous as the low growl of thunder: Dad puffed furiously on his cigarette. "And you can't get ahead if people know you've been a Reader. That's them, don't they?" "Sure, son. One person in ten thousand might reach the point where his corporation or bureau will teach him to read. But you prove your ability and loyalty first. By the time you're 35 or 40, they might want you to learn to read. But for young people and children—well, it just isn't done. Why, the President himself wasn't trusted to learn till he was nearly fifty!" giving orders instead of carrying them. Then I'll learn to read, too. That's the right way to do it." Ronnie shifted uncomfortably on the hassock. "But can't a Reader get a job that's not so important. Like a barber or a plumber or—" "Damn it, son, how could you even think of being a Reader? You've got at school. Ronnie, don't you realize I'd lose my job if people knew I had a Reader for a son?" "B—but, Daddy—" Dad jumped to his feet. "I hate to say it, Edith, but we've got to put this boy in a reformatory. Maybe a good memory-wash will take some of the nonsense out of him!" Dad stood very tall and very stiff, not even looking at him. "They won't take your brain, just your memory for the past two years." A corner of Mom's mouth twitched. "David, I didn't want anything like have the mind of a six-year-old child again. He'd have to start to school all over again." antique clock. All movement seemed frozen, as if the room lay at the bottom of a cold, thick sea. "David," Mom finally said. "Yes?" Dad interrupted: "But he'd still remember how to read, unconsciously anyway. Even permi-hypnosis would wear off in time. The boy can't keep going to psychiatrists for the rest of his life." Thoughtfully he laced his fingers together. "Edith, what kind of a book was he reading?" A tremor passed through Mom's slender body. "There were three books on his bed. I'm not sure which one he was actually reading." Dad groaned. " Three Dad gingerly turned a cover. His lips curled in disgust as if he were "A hundred years old," he repeated. His mouth became a hard, thin line. "Edith, I think I know why Ronnie wanted to read, why he fell into the trap so easily." Dad nodded at the clock, and the slow, smouldering anger returned to Mom's face paled. "I don't understand." "You've interested Ronnie in old things. To a child in its formative things. It was natural for him to be attracted by books. And we were just too stupid to realize it." Mom whispered hoarsely, "I'm sorry, David." Hot anger flashed in Dad's eyes. "It isn't enough to be sorry. Don't complete memory-wash. He'll never know we existed, and he'll never bother us again." Mom ran up to Dad. She put her hands on his shoulders. Great sobs burst from her shaking body. "You can't, David! I won't let—" "Edith," he said crisply, "just what was Ronnie reading? What's the name of this book?" " The—The Adventures of Tom Sawyer ," said Mom through her sobs. He grabbed the second book, held it before her shimmering vision. "And the name of this?" " Tarzan of The Apes. " Mom's voice was a barely audible croak. "Who's the author?" "Edgar Rice Burroughs." " He spat the name as if it were acid on his tongue. "Edith, you can read !" Mom sucked in her sobs. Her chalk-white cheeks were still streaked with rivulets of tears. "I'm sorry, David. I've never told anyone—not even Ronnie. I haven't "A good wife." Dad sneered. His face was so ugly that Ronnie looked away. Mom continued, "I—I learned when I was just a girl. I was young like Ronnie. You know how young people are—reckless, eager to do forbidden things." "You lied to me," Dad snapped. "For ten years you've lied to me. Why did you want to read, Edith? Why? " Mom was silent for a few seconds. She was breathing heavily, but no longer crying. A calmness entered her features, and for the first time Her words echoed in the room until absorbed by the ceaseless, ticking clock. Mom stood straight and unashamed. Dad's gaze traveled slowly to Ronnie, to Mom, to the clock, back and forth. At last he said, "Get out." Mom stared blankly. "Get out. Both of you. You can send for your things later. I never want to see either of you again." "I said get out !" was rising. Mom shivered in her thin house cloak. "Hi. Who's that? Your mom?"

<question>:
How did Dad realize that Mom could read?

<options>:
A Mom was able to read the titles and authors of the books
B She was fired from her job for reading
C Dad caught Mom reading in secret
D Mom told him that she could read

<answer>:

A