I lost my sight when I was four years old

题目：

I lost my sight when I was four years old by falling off a box car in a freight yard in Atlantic City and landing on my head. Now I am thirty-two. I can vaguely remember the brightness of sunshine and what color red is. It would be wonderful to see again, but a disaster can do strange things to people. It occurred to me the other day that I might not have come to love life as I do if I hadn’t been blind. I believe in life now. I am not so sure that I would have believed in it so deeply, otherwise. I don’t mean that I would prefer to go without my eyes. I simply mean that the loss of them made me appreciate the more what I had left.
Life, I believe, asks a continuous series of adjustments to reality. The more readily a person is able to make these adjustments, the more meaningful his own private world becomes. The adjustment is never easy. I felt helpless and afraid. But I was lucky. My parents and my teachers saw something in me--a potential to live, you might call it--which I didn’t see, and they made me want to fight it out with blindness.
The hardest lesson I had to learn was to believe in myself. That was basic, If I hadn’t been able to do that, I would have collapsed and become a chair rocker on the front perch for the rest of my life. When I say belief in myself I am not talking about simply the kind of self-confidence that helps me down an unfamiliar staircase alone. That is part of it. But I mean something bigger than that: an assurance that I am, despite imperfections, a real, positive person; that somewhere in the sweeping, intricate pattern of people there is a special place where I can make myself fit.
It took me years to discover and strengthen this assurance. It had to start with the most elementary things. Once a man gave me an indoor baseball. I thought he was making fun of me and I was hurt. "I can’t use this," I said. "Take it with you," he urged me, "and roll it around." The words stuck in my head. "Roll it around!" By rolling the ball I could hear where it went. This gave me an idea how to achieve a goal I had thought impossible: playing baseball. At Philadelphia’s Overbrook School for the Blind I invented a successful variation of baseball. We called it ground ball.

For the writer, the most difficult thing is to ______.
A. be sure that his future can be positive too.
B. be sure that he is a perfect person.
C. be sure that he can play baseball just like everybody else.
D. adjust himself to the reality.

All my life I have set ahead of me a series of goals and then tried to reach them, one at a time. I had to learn my limitations. It was no good to try for something I knew at the start was wildly out of reach because that only invited the bitterness of failure. I would fail sometimes anyway but on average I made progress.