单选题：下列程序段的输出结果是

下列程序段的输出结果是 @[A](2)
```c++
#include
int main(void)
{
int x = 100, a = 10, b = 20, ok1 = 5, ok2 = 0;
if (a < b)
if (b != 15)
if (!ok1)x = 1;
else if (ok2)x = 10;
x = -1;
printf("%d\n", x);
return 0;
}
```
A. -1
B. 0
C. 1
D. 不确定的值





A.-1
B.0
C.1
D.不确定的值


答案：A