#include "bits/stdc++.h"
using namespace std;
#define forR(i, x) for(int i = 0; i < (x); ++i)
#define REP(i, a, b) for(int i = (a); i < (b); ++i)
typedef long long ll;
struct pii{int a, b;};
const int MN = 3e5 + 10, MQ = 3e5 + 10;
struct query{int l, r, i;};
ll c[MN];
ll ans[MQ];
vector<query> byR[MN];
ll ti[MN], buf[MN];
bool pos[MN];
struct invl{int l, r; ll ti;};
ll ceilDiv(ll a, ll b){
return (a-1)/b+1;
}
int main() {
int n;
ll d; cin >> n >> d;
REP(i, 1, n+1) {
pos[i] = true;
}
REP(i, 1, n+1) cin >> c[i];
int q; cin >> q;
forR(i, q){
query cur={}; cin >> cur.l >> cur.r;
cur.i = i;
byR[cur.r].push_back(cur);
}
vector<invl> ivs;
REP(i, 1, n+1){
if(i == 1 || c[i] >= c[i-1] - d*ti[i-1]) {
if(!ivs.empty()) ivs.back().ti = (c[i] - (c[i-1]-d*ti[i-1])) / d;
ivs.push_back({i, i, 83742});
} else {
ll ct = ceilDiv((c[i-1]-d*ti[i-1]) - c[i], d);
while(ct > 0){
if(ivs.size() == 1){
for(int j = ivs.back().l; j <= ivs.back().r; ++j) ti[j] += ct;
ct = 0;
} else {
invl& sLast = ivs[(int) ivs.size() - 2];
if(sLast.ti > ct) {
for(int j = ivs.back().l; j <= ivs.back().r; ++j) ti[j] += ct;
sLast.ti -= ct;
ct = 0;
} else {
for(int j = ivs.back().l; j <= ivs.back().r; ++j) ti[j] += sLast.ti;
ct -= sLast.ti;
sLast.r = ivs.back().r;
sLast.ti = 283742;
ivs.pop_back();
}
}
}
ivs.back().r = i;
}
for(auto [l, r, ind] : byR[i]){
if(c[l] - d*ti[l] < 0) ans[ind] = -1;
else {
for(int j = l; j <= i; ++j){
ans[ind] += ti[j];
}
}
}
}
forR(i, q) cout << ans[i] << '\n';
}
