import sys
input = sys.stdin.readline

mod = 998244353
for _ in range(int(input())):
    n, m, l, r = map(int, input().split())
    ans = (r - l + 1) % mod
    ans += (r - l + 1) * (m // (n - 1)) % mod
    ans %= mod
    if m > 0 and n > 2 and m % (n - 1) == 0:
        ans += (r // (n - 1) - (l - 1) // (n - 1)) % mod
        ans %= mod
    print(ans)