AMC 10A 2002 Problem 9

Suppose A, B, and C are three numbers for which 1001 C-2002 A=4004 and 1001 B+3003 A=5005. The average of the three numbers A, B, and C is

Answer Choices
A. 1
B. 3
C. 6
D. 9
E. not uniquely determined