Read the following excerpt from "A Sunrise on the Veld."
"Suddenly it all rose in him: it was unbearable. He leaped up into the air, shouting and yelling wild, unrecognizable noises. Then he began to run, not carefully, as he had before, but madly, like a wild thing. He was clean crazy, yelling mad with the joy of living and a superfluity of youth. He rushed down the vlei under a tumult of crimson and gold, while all the birds of the world sang about him. He ran in great leaping strides, and shouted as he ran, feeling his body rise into the crisp rushing air and fall back surely onto sure feet; and thought briefly, not believing that such a thing could happen to him, that he could break his ankle any moment, in this thick tangled grass."
What becomes “unbearable” to the boy?
A. His uncontainable joy.
B. His fear of the jungle noises.
C. The danger of the high cliff.
D. His ability to leap like a buck.