#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
int n, d, q, A[300005], val[300005], P[300005], grr[300005];
vector <pii> Q;
int ans[300005];
pi brr[300005];
void dnc(int l, int r, vector <pii> &qu){
if(l >= r)return;
int mid = (l + r) >> 1;
vector <pii> lft, rgt, gd;
for(auto i : qu){
if(i.fi > mid)rgt.push_back(i);
else if(i.se.fi <= mid)lft.push_back(i);
else gd.push_back(i);
}
dnc(l, mid, lft);
dnc(mid + 1, r, rgt);
brr[mid + 1] = {0, 0};
int cur_sum = 0, cur_one = 0;
stack <pi> s;
s.push({1e18, mid});
for(int i = mid + 2; i <= r; i++){
if(A[i] >= A[i - 1])s.push({(A[i] - A[i - 1]) / d, i - 1});
else{
int tmp = (A[i - 1] - A[i] + d - 1) / d;
cur_sum += tmp * (i - 1 - s.top().se);
if(s.top().se == mid)cur_one += tmp;
while(!s.empty() && tmp){
pi x = s.top();
s.pop();
if(x.fi > tmp){
x.fi -= tmp;
s.push(x);
break;
}
tmp -= x.fi;
assert(!s.empty());
cur_sum += (x.se - s.top().se) * tmp;
if(s.top().se == mid)cur_one += tmp;
}
}
brr[i] = {cur_sum, cur_one};
}
int prv = A[mid], cur = 0;
brr[mid] = {0, A[mid]};
val[mid] = 0;
for(int i = mid - 1; i >= l; i--){
if(A[i] <= prv){
brr[i] = {cur, A[i]};
val[i] = (prv - A[i]) / d;
prv = A[i];
continue;
}
int ops = (A[i] - prv + d - 1) / d;
val[i] = 0;
prv = A[i] - ops * d;
cur += ops;
brr[i] = {cur, prv};
}
P[l - 1] = grr[l - 1] = 0;
for(int i = l; i <= mid; i++)P[i] = P[i - 1] + val[i], grr[i] = grr[i - 1] + val[i] * (i + 1);
for(auto i : gd){
int lend = i.fi, rend = i.se.fi;
if(brr[lend].se < 0 || A[mid + 1] - brr[rend].se * d < 0){
ans[i.se.se] = -1;
continue;
}
int lo = lend, hi = mid, tmp = lo, ops = 0, ops_one = 0;
int rem = A[mid + 1] - brr[rend].se * d;
int req = (A[mid] - rem + d - 1) / d;
req = max(req, 0ll);
while(lo <= hi){
int mm = (lo + hi) >> 1;
if(P[mid] - P[mm - 1] >= req)tmp = mm, lo = mm + 1;
else hi = mm - 1;
}
//cout << lend << ' ' << rend << ' ' << tmp << ' ' << req << ' ' << rem << '\n';
//cout << P[mid] - P[tmp - 1] << '\n';
if(P[mid] - P[tmp - 1] <= req){
ops = req * (mid - lend + 1) - (grr[mid] - grr[tmp - 1]) + lend * (P[mid] - P[tmp - 1]);
if(tmp == lend)ops_one += req - P[mid] + P[tmp - 1];
}
else{
int x = P[mid] - P[tmp];
ops += req * (mid - lend + 1) - (grr[mid] - grr[tmp]) + lend * x;
rem = req - x;
ops -= rem * (tmp + 1);
ops += lend * rem;
}
if(brr[lend].se - ops_one * d < 0)ans[i.se.se] = -1;
else ans[i.se.se] = brr[lend].fi + brr[rend].fi + ops;
}
}
void solve(){
cin >> n >> d;
for(int i = 1; i <= n; i++)cin >> A[i];
for(int i = 1; i < n; i++){
if(A[i] < A[i + 1]){
val[i] = (A[i + 1] - A[i]) / d;
}
P[i] = P[i - 1] + val[i];
grr[i] = grr[i - 1] + val[i] * (i + 1);
}
cin >> q;
/*
while(q--){
int l, r; cin >> l >> r;
int cur = 0, f = 1, prv = A[r];
for(int i = r - 1; i >= l; i--){
int df = A[i] - prv;
if(df < 0){
prv = A[i];
continue;
}
int tmp = (df + d - 1) / d;
if(A[i] - tmp * d < 0){
f = 0;
break;
}
prv = A[i] - tmp * d;
cur += (df + d - 1) / d;
}
if(!f){
cout << -1 << '\n';
continue;
}
cout << cur << '\n';
}
*/
for(int i = 1; i <= q; i++){
int l, r;
cin >> l >> r;
if(l == r)ans[i] = 0;
else Q.push_back({l, {r, i}});
}
dnc(1, n, Q);
for(int i = 1; i <= q; i++)cout << ans[i] << '\n';
}
main(){
ios::sync_with_stdio(0);cin.tie(0);
int tc = 1;
//cin >> tc;
for(int tc1=1;tc1<=tc;tc1++){
// cout << "Case #" << tc1 << ": ";
solve();
}
}
