Data Structure Arrays Interview Question:

What will be output if you will execute following c code?
#include<stdio.h>
union group{
char xarr[2][2];
char yarr[4];
};
void main(){
union group x={'A','B','C','D'};
printf("%c",x.xarr[x.yarr[2]-67][x.yarr[3]-67]);
}