#include <stdio.h>

unsigned long long int fact(int num, int min);

int main(){
	int a, b, k, c, i;
	scanf("%d %d %d %d", &a, &b, &k, &c);
	unsigned long long int result = 0;
	

	if((a != c && b!= c)||k<=0)
		{
		printf("0");
		return 0;
		}
	if (k%2 == 0){
	i = 0;
	while(i < k-i){
		result += (fact(k, k-i) * k)/ fact(i, 1);
		result %= 1000000007;
		i++;
		//printf("%llu\n", result);
		}

	result += (fact(k, i) * k/2) / fact(k-i, 1);
	result %= 1000000007;
	}
	else{
	i = 0;
	while(i <= k-i){
		result += (fact(k, k-i) * k) / fact(i, 1);
		result %= 1000000007;
		i++;
		}
	}

	printf("%llu", result);
	
	return 0;
}

unsigned long long int fact(int num, int min){
	unsigned long long int sum = 1;
	int i;	


	for(i = num; i > min; i--){
		sum *= i;
		sum %= 1000000007;
	}
	
	//printf("num: %d min: %d result: %d \n", num, min, sum);
	return sum;
}