There was a time in the USA when the money spent on educating a black child was just one fourth of _____ spent on each white child.

A. it                             B. one        C. that         D. what

（2010·黑龙江大庆实验中学高三第二次月考）25. There was a time in the USA when the money spent on educating a black child was just one fourth of _____ spent on each white child.

A. it        B. one  C. that          D. what