单选题：若有以下说明：int ia[12]={1,2,3,4,5,6,7,8,9,10,11,12};char ch='a',cg=97

若有以下说明：
int ia[12]={1,2,3,4,5,6,7,8,9,10,11,12};
char ch='a',cg=97;
则数值为4的表达式是（ ）
@[D](2)

A. ia[cg-ch]
B. ia[4]
C. ia['d'-'c']
D. ia['d'-ch]



A.ia[cg-ch]
B.ia[4]
C.ia['d'-'c']
D.ia['d'-ch]


答案：D