Help me in solving EVENTUAL problem

help
,
1

My issue

why my code is comming runtime Error

My code

#include <stdio.h>
#include <string.h>

int main() {
    int t;
    scanf("%d", &t);

    while (t--) {
        int n, c;
        char a[101]; 
        char ans[4] = "YES";
        
        scanf("%d %s", &n, a);

        if (n % 2 != 0) {
            strcpy(ans, "NO");
        } else {
            for (int i = 0; i < n; i++) {
                c = 0;
                for (int j = 0; j < n; j++) {
                    if (a[i] == a[j]) {
                        c++;
                    }
                }
                if (c % 2 != 0) {
                    strcpy(ans, "NO");
                    break;
                }
            }
        }

        printf("%s\n", ans);
    }

    return 0;
}

Learning course: Roadmap to 3*
Problem Link: https://www.codechef.com/learn/course/klu-roadmap-3star/KLURMP300A/problems/EVENTUAL