using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var t = NN;
        var ans = new long[t];
        for (var u = 0; u < t; ++u)
        {
            var c = NList;
            var (n, m, l, r) = (c[0], c[1], c[2], c[3]);
            ans[u] = Incline(n, m, l, r);
        }
        WriteLine(string.Join("\n", ans));
    }
    static readonly int mod = 998_244_353;
    static long Incline(long n, long m, long l, long r)
    {
        var ans = F(n, m, r);
        if (l > 0) ans = (ans + mod - F(n, m, l - 1)) % mod;
        return ans;
    }
    static long F(long n, long m, long r)
    {
        return (m / (n - 1) % mod * (r % mod + 1) % mod + G(n, m, r)) % mod;
    }
    static long G(long n, long m, long r)
    {
        return (r / (n - 1) % mod * (m % (n - 1) + 1) % mod + Math.Min(r % (n - 1), m % (n - 1)) + 1) % mod;
    }
}