#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 300'000 + 10,
MAX = 1'000'000'000'000;
int n, d, q;
int c[N];
vector<pair<int, int>> save[N];
namespace IT {
int f[N << 2], lazy[N << 2];
void push(int id, int l, int r) {
if (!lazy[id]) return;
int mid = (l + r) >> 1;
f[id << 1] += lazy[id] * (mid - l + 1); f[id << 1 | 1] += lazy[id] * (r - mid);
lazy[id << 1] += lazy[id]; lazy[id << 1 | 1] += lazy[id];
lazy[id] = 0;
}
void update(int id, int l, int r, int u, int v, int x) {
if (v < l || r < u) return;
if (u <= l && r <= v) {
f[id] += x * (r - l + 1);
lazy[id] += x;
return;
}
push(id, l, r);
int mid = (l + r) >> 1;
update(id << 1, l, mid, u, v, x); update(id << 1 | 1, mid + 1, r, u, v, x);
f[id] = f[id << 1] + f[id << 1 | 1];
}
int query(int id, int l, int r, int u, int v) {
if (v < l || r < u) return 0;
if (u <= l && r <= v) return f[id];
push(id, l, r);
int mid = (l + r) >> 1;
return query(id << 1, l, mid, u, v) + query(id << 1 | 1, mid + 1, r, u, v);
}
}
int answer[N];
int32_t main() {
cin.tie(0)->sync_with_stdio(0);
cin >> n >> d;
for (int i = 1; i <= n; ++i) cin >> c[i];
cin >> q;
for (int i = 1; i <= q; ++i) {
int l, r; cin >> l >> r;
save[r].push_back({l, i});
}
auto get = [&](int i) { return c[i] - d * IT::query(1, 1, n, i, i); };
stack<int> st;
for (int i = 1; i <= n; ++i) {
int r = i;
while (st.size()) {
int l = st.top(), x = get(r - 1), y = get(r);
if (x <= y) break;
IT::update(1, 1, n, l, r - 1, (x - y - 1) / d + 1);
r = l; st.pop();
}
st.push(r);
for (auto [l, id] : save[i])
answer[id] = (get(l) < 0 ? -1 : IT::query(1, 1, n, l, i));
}
for (int i = 1; i <= q; ++i) cout << answer[i] << "\n";
}
