#include <bits/stdc++.h>
#define int long long
#define pii pair <int, int>
using namespace std;
const int maxN = 3e5 + 5;
int n, D;
int c[maxN];
int res[maxN];
vector <pii> off[maxN];
struct ST {
vector <int> st, lazy;
inline void init (int _n) {
st.resize (_n * 4, 0LL);
lazy.resize (_n * 4, 0LL);
}
inline void push (int id, int l, int r) {
int &t = lazy[id];
if (t != 0) {
int mid = (l + r) >> 1;
st[id * 2] += (mid - l + 1) * t;
lazy[id * 2] += t;
st[id * 2 + 1] += (r - (mid + 1) + 1) * t;
lazy[id * 2 + 1] += t;
}
t = 0;
return;
}
void upd (int id, int l, int r, int u, int v, int val) {
if (v < l || u > r) {
return;
}
if (u <= l && r <= v) {
st[id] += (r - l + 1) * val;
lazy[id] += val;
return;
}
push (id, l, r);
int mid = (l + r) >> 1;
upd (id * 2, l, mid, u, v, val);
upd (id * 2 + 1, mid + 1, r, u, v, val);
st[id] = (st[id * 2] + st[id * 2 + 1]);
return;
}
int get (int id, int l, int r, int u, int v) {
if (v < l || u > r) {
return 0;
}
if (u <= l && r <= v) {
return st[id];
}
push (id, l, r);
int mid = (l + r) >> 1;
int tL = get (id * 2, l, mid, u, v);
int tR = get (id * 2 + 1, mid + 1, r, u, v);
return (tL + tR);
}
};
ST T;
signed main () {
ios_base :: sync_with_stdio (0);
cin.tie (0);
cin >> n >> D;
T.init (n);
for (int i = 1; i <= n; i ++) {
cin >> c[i];
}
int q;
cin >> q;
for (int i = 1; i <= q; i ++) {
int l, r;
cin >> l >> r;
off[r].push_back ({l, i});
}
stack <int> st;
for (int i = 1; i <= n; i ++) {
int cur = i;
while (!st.empty ()) {
int x = c[cur - 1] - D * T.get (1, 1, n, cur - 1, cur - 1);
int y = c[cur] - D * T.get (1, 1, n, cur, cur);
if (x <= y) {
break;
}
int need = (x - y - 1) / D + 1;
T.upd (1, 1, n, st.top (), cur - 1, need);
cur = st.top ();
st.pop ();
}
st.push (cur);
for (auto [l, id] : off[i]) {
if ((c[l] - D * T.get (1, 1, n, l, l)) < 0) {
res[id] = -1;
}
else {
res[id] = T.get (1, 1, n, l, i);
}
}
}
for (int i = 1; i <= q; i ++) {
cout << res[i] << '\n';
}
}
