B

#include <bits/stdc++.h>

using namespace std;

#define ll     long long
#define _test   int _TEST; cin>>_TEST; while(_TEST--)

int main()
{
    _test
    {
        ll int m, k, a, b;
        cin>>m>>k>>a>>b;

        ll int tmp = (m/k)*k;
        tmp = min(tmp, b*k);

        tmp = m - tmp;

        m = max(0ll, tmp-a);

        ll int ans = ((m/k) + (m%k));

        if(a >= (k - m%k))
        {
            ll int ans2 = 1 + (m/k);
            ans = min(ans, ans2);
        }

        cout<<ans<<"\n";
    }
}