4 вариант

#include <stdio.h>

int main(){
    int arr[22];

    for (int i = 0; i < 22; ++i) {
        scanf("%d", &arr[i]);
    }

    int mult = 1;
    for (int i = 0; i < 22; ++i) {
        mult *= arr[i] % 4 == 2 ? arr[i] : 1;
    }

    printf("%d", mult);

    return 0;
}