#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 524288;
ll t[2 * N];
ll t2[2 * N];
void build() {
for (int i = N - 1; i >= 1; --i) {
t[i] = min(t[2 * i], t[2 * i + 1]);
t2[i] = max(t2[2 * i], t2[2 * i + 1]);
}
}
ll query(int L, int R, int ind = 1, int l = 0, int r = N - 1) {
if (L <= l && r <= R) return t[ind];
if (L > r || l > R) return (1LL << 60);
int md = (l + r) / 2;
return min(query(L, R, 2 * ind, l, md), query(L, R, 2 * ind + 1, md + 1, r));
}
ll query2(int L, int R, int ind = 1, int l = 0, int r = N - 1) {
if (L <= l && r <= R) return t2[ind];
if (L > r || l > R) return 0LL;
int md = (l + r) / 2;
return max(query2(L, R, 2 * ind, l, md), query2(L, R, 2 * ind + 1, md + 1, r));
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
ll d;
cin >> n >> d;
vector<ll> oc(n);
for (auto & x: oc) {
cin >> x;
}
vector<ll> p(n, 0);
ll last = (1LL << 60);
for (int i = n - 1; i >= 0; --i) {
if (oc[i] <= last) {
last = oc[i];
} else {
p[i] = ((oc[i] - last) + d - 1) / d;
last = oc[i] - p[i] * d;
}
ll nd = max(0LL, -last);
t2[i + N] = (nd + d - 1) / d;
// cout << "!!! " << last << ' ' << p[i] << ' ' << t2[i + N] << '\n';
assert(t2[i + N] <= p[i]);
}
for (int i = 0; i < n; ++i) {
t[i + N] = p[i];
if (i) p[i] += p[i - 1];
}
build();
auto get = [&] (int l, int r) -> ll {
return p[r] - (l ? p[l - 1] : 0LL);
};
int q; cin >> q;
while (q--) {
int ql, qr;
cin >> ql >> qr;
ql--; qr--;
ll s = get(ql, qr);
ll all = query(ql, qr);
ll nd = query2(ql, qr); // all must be >= nd
// cout << s << ' ' << all << ' ' << nd << '\n';
if (all < nd) {
cout << "-1\n";
} else {
cout << (s - all * (1LL + qr - ql)) << "\n";
}
}
}
