def solve_(N, M, b):
	if b == -1:
		return 0
	ans = M // (N - 1) * (b + 1)
	ans += (M % (N - 1) + 1) * (b // (N - 1))
	ans += max(M % (N - 1) + 1, b % (N - 1))
	return ans

def solve(N, M, L, R):
	return solve_(N, M, R) - solve_(N, M, L - 1)

T = int(input())
for i in range(T):
	N, M, L, R = map(int, input().split())
	print(solve(N, M, L, R) % 998244353)