#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define pb push_back
#define ff first
#define ss second
const ll inf = numeric_limits<ll> :: max();
struct DS{
vector<pair<ll, ll>> t;
vector<ll> p;
int n;
DS(int ns){
n = ns;
t.resize(4 * n, {0, 0});
p.assign(4 * n, -1);
}
void push(int& v, int& tl, int& tr){
if (p[v] == -1) return;
int tm = (tl + tr) / 2, vv = 2 * v;
t[vv].ff = p[v] * (tm - tl + 1);
t[vv + 1].ff = p[v] * (tr - tm);
t[vv].ss = t[vv + 1].ss = p[vv] = p[vv + 1] = p[v];
p[v] = -1;
}
int find(int v, int tl, int tr, ll& x){
if (tl == tr) return tl;
int tm = (tl + tr) / 2, vv = 2 * v;
push(v, tl, tr);
if (t[vv].ss > x){
return find(vv, tl, tm, x);
}
return find(vv + 1, tm + 1, tr, x);
}
void ch(int v, int tl, int tr, int& l, int& r, ll& x){
if (l > tr || r < tl) return;
if (l <= tl && tr <= r){
t[v].ff = x * (tr - tl + 1);
t[v].ss = p[v] = x;
return;
}
int tm = (tl + tr) / 2, vv = 2 * v;
push(v, tl, tr);
ch(vv, tl, tm, l, r, x);
ch(vv + 1, tm + 1, tr, l, r, x);
t[v].ff = t[vv].ff + t[vv + 1].ff;
t[v].ss = max(t[vv].ss, t[vv + 1].ss);
}
void upd(int p, ll x){
int t = min(find(1, 1, n, x), p);
ch(1, 1, n, t, p, x);
}
ll get(int v, int tl, int tr, int& l, int& r){
if (l > tr || r < tl) return 0;
if (l <= tl && tr <= r) return t[v].ff;
int tm = (tl + tr) / 2, vv = 2 * v;
push(v, tl, tr);
return get(vv, tl, tm, l, r) + get(vv + 1, tm + 1, tr, l, r);
}
ll get(int l, int r){
return get(1, 1, n, l, r);
}
};
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n; ll d; cin>>n>>d;
vector<ll> a(n + 1);
for (int i = 1; i <= n; i++){
cin>>a[i];
}
vector<ll> x(n);
for (int i = 1; i < n; i++){
x[i] = floor(1.0 * (a[i + 1] - a[i]) / d);
}
vector<ll> y(n + 1);
for (int i = 2; i <= n; i++){
y[i] = y[i - 1] + x[i - 1];
}
vector<ll> p(n + 1);
for (int i = 1; i <= n; i++){
p[i] = p[i - 1] + y[i];
}
int q; cin>>q;
vector<pii> end[n + 1];
for (int i = 1; i <= q; i++){
int l, r; cin>>l>>r;
end[r].pb({l, i});
}
vector<ll> out(q + 1);
DS T(n);
for (int r = 1; r <= n; r++){
T.upd(r, y[r]);
for (auto [l, ii]: end[r]){
ll h = T.get(l, l) - y[l];
if ((a[l] + h * d) < 0){
out[ii] = -1;
continue;
}
out[ii] = (p[r] - p[l - 1]) - T.get(l, r);
}
}
for (int i = 1; i <= q; i++){
cout<<out[i]<<"\n";
}
}
