#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = double;
const int MAXN = 3e5;
ll d;
struct LazySeg {
ll lz[4 * MAXN + 1];
ll mnV[4 * MAXN + 1], sum[4 * MAXN + 1];
int n;
void init(int n) {
this->n = n;
}
void push(int i, int l, int r) {
if (lz[i] == 0) return;
sum[i] += lz[i] * (r - l + 1);
mnV[i] -= lz[i] * d;
if (l < r) {
lz[i * 2] += lz[i];
lz[i * 2 + 1] += lz[i];
}
lz[i] = 0;
}
void combine(int i, int j, int k) {
sum[i] = sum[j] + sum[k];
mnV[i] = min(mnV[j], mnV[k]);
}
array<ll, 2> combine_query(int j, array<ll, 2> nres = {0, LLONG_MAX}) {
array<ll, 2> res = nres;
res[0] += sum[j];
res[1] = min({res[1], mnV[j]});
return res;
}
void turnon(int i, int l, int r, int qp, ll val) {
push(i, l, r);
if (l == r) {
mnV[i] = val;
return;
}
int m = (l + r) / 2;
if (qp <= m) turnon(i * 2, l, m, qp, val);
else turnon(i * 2 + 1, m + 1, r, qp, val);
combine(i, i * 2, i * 2 + 1);
}
void turnon(int qp, ll val) {turnon(1, 1, n, qp, val);}
void update(int i, int l, int r, int ql, int qr, ll val) {
push(i, l, r);
if (ql > r || l > qr) return;
if (ql <= l && r <= qr) {
lz[i] += val;
push(i, l, r);
return;
}
int m = (l + r) / 2;
update(i * 2, l, m, ql, qr, val);
update(i * 2 + 1, m + 1, r, ql, qr, val);
combine(i, i * 2, i * 2 + 1);
}
void update(int ql, int qr, ll val) {update(1, 1, n, ql, qr, val);}
array<ll, 2> query(int i, int l, int r, int ql, int qr) {
push(i, l, r);
if (ql <= l && r <= qr) {
return {mnV[i], sum[i]};
}
array<ll, 2> res = {0, LLONG_MAX};
int m = (l + r) / 2;
if (ql <= m) res = combine_query(i * 2);
if (m + 1 <= qr) res = combine_query(i * 2 + 1, res);
return res;
}
ll query(int ql, int qr) {
if (ql == qr) return 0;
array<ll, 2> q = query(1, 1, n, ql, qr);
if (q[1] < 0) return -1;
return q[0];
}
} tree;
int main() {
//~ ofstream cout("out.txt");
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n >> d;
tree.init(n);
vector<vector<array<int, 2>>> quer(n + 1);
vector<ll> a(n + 1);
for (int i = 1; i <= n; ++i) {
cin >> a[i];
}
int q;
cin >> q;
for (int i = 0; i < q; ++i) {
int l, r;
cin >> l >> r;
quer[r].push_back({l, i});
}
vector<array<ll, 2>> st = {{0, (ll)1e18}};
vector<ll> res(q);
for (int i = 2; i <= n; ++i) {
tree.turnon(i - 1, a[i - 1]);
if (a[i] >= a[i - 1]) {
st.push_back({i - 1, (a[i] - a[i - 1]) / d});
} else {
ll need = (a[i - 1] - a[i] + d - 1) / d;
int pos = i;
while (need > 0) {
auto& [ni, have] = st.back();
ll take = min(need, have);
tree.update(ni + 1, pos - 1, take);
need -= take;
have -= take;
if (have == 0) {
pos = ni + 1;
st.pop_back();
}
}
}
for (auto [l, j] : quer[i]) {
res[j] = tree.query(l, i);
}
}
for (int i = 0; i < q; ++i) {
cout << res[i] << "\n";
}
}
