单选题：Given the definitions：
Given the definitions：
```
#define type1 char *
typedef char *type2;
type1 s1, s2;
type2 s3, s4;
```
Among the followings, which group contains all the identifiers that are character pointers? @[C](2)
A. `s1, s3`
B. `s1, s2, s3`
C. `s1, s3, s4`
D. `s1, s2, s3, s4`
A.`s1, s3`
B.`s1, s2, s3`
C.`s1, s3, s4`
D.`s1, s2, s3, s4`
答案：C
```
#define type1 char *
typedef char *type2;
type1 s1, s2;
type2 s3, s4;
```
Among the followings, which group contains all the identifiers that are character pointers? @[C](2)
A. `s1, s3`
B. `s1, s2, s3`
C. `s1, s3, s4`
D. `s1, s2, s3, s4`
A.`s1, s3`
B.`s1, s2, s3`
C.`s1, s3, s4`
D.`s1, s2, s3, s4`
答案：C
