Find the output of the program?

#include <stdio.h>
#define L 10
int main(){
    int a =10;
    switch (a,a<<2){
        case L:printf("a==L");     break;
        case L*2 : printf("a = L* 2\n");     break;
        case L*4 : printf("a = L* 4\n");    break;
        default: printf("Error\n");
    }
}