【单选题】

Family X’s gross income is the sum of M r．X’s income and Mrs．X’s income．In1983 Mr．and Mrs．X each had an income of $25，000．If Mr．X’s income increased by 10 percent from 1983 to 1984，by what percent did Mrs．X’s income decrease for the same period

A、10%

B、15%

C、20%

D、25% E、30%