// author: erray
#include <bits/stdc++.h>
#ifdef DEBUG
#include "debug.h"
#else
#define debug(...) void(37)
#endif
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int N;
int64_t D;
cin >> N >> D;
vector<int64_t> C(N);
for (int i = 0; i < N; ++i) {
cin >> C[i];
}
reverse(C.begin(), C.end()); //stupid
vector<int64_t> suf_md(N);
suf_md[N - 1] = C[N - 1] % D;
for (int i = N - 2; i >= 0; --i) {
suf_md[i] = suf_md[i + 1] + (D + (C[i] - C[i + 1]) % D) % D;
}
vector<int64_t> a(N);
for (int i = 0; i < N; ++i) {
a[i] = C[i] - suf_md[i];
assert(a[i] % D == 0);
a[i] /= D;
}
vector<int64_t> pref(N + 1);
for (int i = 0; i < N; ++i) {
pref[i + 1] = pref[i] + a[i];
}
int Q;
cin >> Q;
vector<int> L(Q), R(Q);
vector<vector<int>> qs(N);
for (int i = 0; i < Q; ++i) {
int ll, rr;
cin >> ll >> rr;
--ll, --rr;
L[i] = N - rr - 1; //this is stupid too
R[i] = N - ll - 1;
qs[L[i]].push_back(i);
}
vector<int64_t> ans(Q);
struct S {
int ind;
int64_t pref;
};
auto Cost = [&](int l, int r) {
return (pref[r + 1] - pref[l]) - a[l] * (r - l + 1);
};
vector<S> st;
st.push_back(S{N, 0});
for (int i = N - 1; i >= 0; --i) {
while (int(st.size()) > 1 && a[st.back().ind] >= a[i]) {
st.pop_back();
}
st.push_back(S{i, st.back().pref + Cost(i, st.back().ind - 1)});
for (auto id : qs[i]) {
int r = R[id];
debug(id, r);
int last = int(lower_bound(st.begin(), st.end(), r, [&](S t, int x) {
return t.ind > x;
}) - st.begin());
if (a[st[last].ind] * D + suf_md[r] < 0) {
ans[id] = -1;
} else {
ans[id] = st.back().pref - st[last].pref + Cost(st[last].ind, r);
}
}
}
for (int i = 0; i < Q; ++i) {
cout << ans[i] << '\n';
}
}
