#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double dou;
#define pii pair<int, int>
#define pb push_back
#define fi first
#define se second
bool maximize(ll &x, ll y ){
if (x < y) {x = y; return true;};
return false;
}
bool minimize(ll &x, ll y){
if (x > y) {x = y; return true;}
return false;
}
struct BIT{
int n;
vector<ll> bit;
BIT(int _n = 0) {
n = _n;
bit.assign(n+1, 0);
}
void update(int k, ll x) {
while (k <= n) {
bit[k] += x;
k += k & (-k);
}
}
ll getsum(int k) {
ll res = 0;
while (k > 0) {
res += bit[k];
k -= k & (-k);
}
return res;
}
ll query(int l, int r) {
return getsum(r)-getsum(l-1);
}
} bitcost, bitsum;
struct query{
int l, r, id;
ll ans;
query(int u, int v, int i) {
l = u;
r = v;
id = i;
}
};
bool cmp1(query a, query b) {
return a.r < b.r;
}
bool cmp2(query a, query b) {
return a.id < b.id;
}
const int maxn = 3e5+5;
int n, q;
ll d, c[maxn], a[maxn];
vector<query> qu;
void input() {
cin >> n >> d;
c[0] = 0;
for (int i = 1; i <= n; i++) {
cin >> c[i];
//manghieu
a[i] = c[i] - c[i-1];
}
cin >> q;
for (int i = 0; i < q; i++) {
int l, r;
cin >> l >> r;
qu.pb(query(l, r, i));
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
//input
input();
//init
bitsum = BIT(n);
bitcost = BIT(n);
sort(qu.begin(), qu.end(), cmp1);
//vector<cou+pos>
vector<pair<ll, int>> avai;
int j = 0;
for (int i = 1; i <= n; i++) {
if (a[i] >= d) {
avai.push_back({a[i]/d, i});
}
else if (a[i] < 0) {
ll x = (-a[i]-1)/d+1;
//need x
//bit update
bitsum.update(i, -x);
bitcost.update(i, (-x)*(n-i+1));
//fix x
while (!avai.empty() && x > 0) {
ll &cou = avai.back().first;
int pos = avai.back().se;
ll decval = min(cou, x);
cou -= decval;
x -= decval;
//bit
bitsum.update(pos, decval);
bitcost.update(pos, decval*(n-pos+1));
if (cou == 0) avai.pop_back();
}
}
// for (int i = 1; i <= n; i++) {
// cout << bitsum.query(i, i);
// }
// cout << "\n";
// for (int i = 1; i <= n; i++) {
// cout << bitcost.query(i, i);
// }
// cout << "\n\n";
//solve queries offline
while (j < q && qu[j].r == i) {
int l = qu[j].l, r = qu[j].r;
ll &ans = qu[j].ans;
++j;
ll sum = bitsum.query(l+1, r);
//start
ans = 0;
if (sum < 0) {
ll can = max(0LL, c[l]/d);
//need: -sum
if (can+sum<0) {
ans = -1;
continue;
}
ans += (-sum)*(r-l+1);
}
ans += bitcost.query(l+1, r)-sum*(n-r);
}
}
sort(qu.begin(), qu.end(), cmp2);
for (int i = 0; i < q; i++) {
cout << qu[i].ans << "\n";
}
}
/*
4 2
3 1 2 1
1
1 3
4 2
0 1 0 1
3
1 2
2 3
1 1
5 1
3 1 4 1 5
3
1 5
2 4
3 5
6 3
16 14 13 8 6 5
4
1 4
2 5
3 3
1 6
*/
