有以下程序

#include <stdio.h>
#include <math.h>
int main() {
    int a = 1, b = 4, c = 2;
    double x = 10.5, y = 4.0, z;
    z = (a + b) / c + sqrt( y ) * 1.2 / c + x;
    printf("%f\n", z);
    return 0;
}

程序运行后的输出结果是(     )