The little boy demonstrated a remarkable_________ ability; his calculation with figures was faster and more accurate than any one of us here.

A．To illustrate the ways to repair his bicycle.
B．To discuss the problems of his bicycle.
C．To tell us how to solve a problem.
D．To show us how to analyze a problem.

A．at all American universities
B．only in elementary and high schools in America
C．for bad students only
D．by some college professors