# https://atcoder.jp/contests/practice2/submissions/58141876
def floor_sum(n: int, m: int, a: int, b: int) -> int:
    res = 0
    while 1:
        if a >= m or a < 0:
            res += n * (n - 1) * (a // m) // 2
            a %= m
        if b >= m or b < 0:
            res += n * (b // m)
            b %= m
        y_max = a * n + b
        if y_max < m:
            break
        n, b = divmod(y_max, m)
        a, m = m, a
    return res

MOD = 998244353

T = int(input())
for _ in range(T):
    N, M, L, R = map(int, input().split())
    bottom = floor_sum(R-L+1, N-1, 1, L)%MOD
    top = floor_sum(R-L+1, N-1, 1, M-R)%MOD
    print((bottom+top+(R-L+1))%MOD)