Structures, Unions, Enums - Programming

Q1:

What will be the output of the program ?
#include<stdio.h>

int main()
{
    enum days {MON=-1, TUE, WED=6, THU, FRI, SAT};
    printf("%d, %d, %d, %d, %d, %d\n", ++MON, TUE, WED, THU, FRI, SAT);
    return 0;
}

A -1, 0, 1, 2, 3, 4

B Error

C 0, 1, 6, 3, 4, 5

D 0, 0, 6, 7, 8, 9

ANS:B - Error

Because ++ or -- cannot be done on enum value.