Three stacks containing equal numbers of c
题型：单项选择题
问题：
Three stacks containing equal numbers of chips are to be made from 9 red chips, 7 blue chips，and 5 green chips．If all of these chips are used and each stack contains at least 1 chip of each color, what is the maximum number of red chips in any one stack ？（）
A．7
B．6
C．5
D．4
E．3