单选题 有以下程序:#include<stdio.h>int f(int a, int b);void main(){ int i=2, p; p=f(i, i+1); printf("%d", p);}int f(int a, int b){ int c; if(a>b) c=3; else if(a==b) c=2; else c=1; return c;}输出结果是( )