#include <bits/stdc++.h>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define piii pair<int, pii>
#define plll pair<long long, pll>
#define tiii array<int, 3>
#define tiiii array<int, 4>
#define ff first
#define ss second
#define ee ss.ff
#define rr ss.ss
typedef long long ll;
const int INF = (int)1e9 + 7;
using namespace std;
vector<pii> qr[303030];
ll seg[1212121];
ll lazy[1212121];
void down(int ind, int s, int e, ll x)
{
seg[ind] += x * (e - s);
lazy[ind] += x;
}
void prop(int ind, int s, int e)
{
if(lazy[ind])
{
int mid = s + e >> 1;
down(ind << 1, s, mid, lazy[ind]);
down(ind << 1 | 1, mid, e, lazy[ind]);
lazy[ind] = 0;
}
}
void upd(int ind, int s, int e, int l, int r, ll x)
{
if(r <= s || e <= l) return;
if(l <= s && e <= r)
{
down(ind, s, e, x);
return;
}
prop(ind, s, e);
int mid = s + e >> 1;
upd(ind << 1, s, mid, l, r, x);
upd(ind << 1 | 1, mid, e, l, r, x);
seg[ind] = seg[ind << 1] + seg[ind << 1 | 1];
}
ll qry(int ind, int s, int e, int l, int r)
{
if(r <= s || e <= l) return 0;
if(l <= s && e <= r) return seg[ind];
prop(ind, s, e);
int mid = s + e >> 1;
return qry(ind << 1, s, mid, l, r) + qry(ind << 1 | 1, mid, e, l, r);
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n; ll d; cin >> n >> d;
ll A[n]; for(auto &i : A) cin >> i;
int T; cin >> T;
for(int i = 0; i < T; ++i)
{
int l, r; cin >> l >> r; --l;
qr[r].push_back({l, i});
}
ll ps[n + 1]; ps[0] = 0;
for(int i = 0; i < n; ++i) ps[i + 1] = ps[i] + A[i];
vector<int> V;
ll ans[T];
for(int r = 1; r <= n; ++r)
{
upd(1, 0, n, r - 1, r, A[r - 1]);
V.push_back(r - 1);
while(V.size() >= 2)
{
ll x = qry(1, 0, n, V.back() - 1, V.back());
ll y = qry(1, 0, n, V.back(), V.back() + 1);
if(x <= y) break;
ll t = ((x - y - 1) / d + 1) * d;
upd(1, 0, n, V[(int)V.size() - 2], V.back(), -t);
V.pop_back();
}
for(auto [l, i] : qr[r])
{
if(qry(1, 0, n, l, l + 1) < 0) ans[i] = -1;
else ans[i] = (ps[r] - ps[l] - qry(1, 0, n, l, r)) / d;
}
// for(int i = 0; i < n; ++i) cout << qry(1, 0, n, i, i + 1) << ' '; cout << endl;
}
for(int i = 0; i < T; ++i) cout << ans[i] << '\n';
}
