#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 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;
lazy[id] += x;
return;
}
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] = min(f[id << 1], f[id << 1 | 1]) + lazy[id];
}
int query(int id, int l, int r, int u, int v) {
if (v < l || r < u) return MAX;
if (u <= l && r <= v) return f[id];
int mid = (l + r) >> 1;
return min(query(id << 1, l, mid, u, v), query(id << 1 | 1, mid + 1, r, u, v)) + lazy[id];
}
}
vector<int> pos;
int dif[N], isErr[N];
int pref[N], prefA[N], prefB[N];
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});
}
pos = {1};
for (int i = 1; i < n; ++i) {
if (c[i] >= c[i + 1]) {
dif[i] = (c[i] > c[i + 1] ? (c[i] - c[i + 1] - 1) / d + 1 : 0);
if (c[i] < dif[i] * d) isErr[i] = true;
pref[i] = pref[i - 1] + dif[i];
prefA[i] = prefA[i - 1] + dif[i] * (i - pos.back() + 1);
prefB[pos.size()] += dif[i] * (i - pos.back() + 1);
} else {
pref[i] = pref[i - 1];
prefA[i] = prefA[i - 1];
pos.push_back(i + 1);
prefB[pos.size()] = prefB[pos.size() - 1];
}
}
pref[n] = pref[n - 1];
prefA[n] = prefA[n - 1];
auto cal = [&](int l, int r) {
int idL = upper_bound(pos.begin(), pos.end(), l) - pos.begin() - 1,
idR = upper_bound(pos.begin(), pos.end(), r) - pos.begin() - 1;
if (idL == idR) {
return prefA[r] - prefA[l - 1] - (pref[r] - pref[l - 1]) * (l - pos[idL]);
}
int edL = pos[idL + 1] - 1, stR = pos[idR];
int ret = prefB[idR] - prefB[idL + 1];
ret += prefA[edL] - prefA[l - 1] - (pref[edL] - pref[l - 1]) * (l - pos[idL]);
ret += prefA[r] - prefA[stR - 1];
return ret;
};
for (int i = 1; i <= n; ++i) {
IT::update(1, 1, n, i, i, c[i] / d);
}
for (int i = 2, it = 1; i <= n; ++i) {
int last = *(upper_bound(pos.begin(), pos.end(), i) - 1);
IT::update(1, 1, n, last, i - 1, -dif[i - 1]);
if (isErr[i - 1]) it = i;
for (; it < i; ++it) {
if (IT::query(1, 1, n, it, i - 1) >= 0) break;
}
for (const auto& [l, id] : save[i]) {
if (l < it) { answer[id] = -1; continue; }
if (l == i) { answer[id] = 0; continue; }
answer[id] = cal(l, i - 1);
}
}
for (int i = 1; i <= q; ++i) cout << answer[i] << "\n";
}
