执行下列程序，k输入为1时的输出结果是()#includeint main(){int k;scanf("%d",&k);switch(k){case 1: printf("%d",k++);case 2: printf("%d",k++);case 3: printf("%d",k++);break;default: printf("Full!");}return 0;}

A. 2
B. 123
C. 1
D. 3