#include<bits/stdc++.h>
using namespace std;
#define int long long
#define in array<int, 2>
#define pb push_back
#define pob pop_back
#define INF (int)1e17
#define fast() ios_base::sync_with_stdio(false); cin.tie(NULL)
const int LOGM = 19;
const int MX = 3e5+5;
signed main()
{
fast();
int n, d;
cin >> n >> d;
vector<int> c(n+1); vector<int> off(n+1, 0);
for(int i = 1; i <= n; i++)
cin >> c[i];
vector<int> a(n+1), pref(n+1, 0); pref[1] = a[1] = c[1]/d;
for(int i = 2; i <= n; i++)
{
off[i] = off[i-1] + ((c[i]%d) < (c[i-1]%d));
a[i] = (c[i]/d) - off[i];
pref[i] = a[i] + pref[i-1];
}
//immediate left that is smaller.
int L[LOGM][n+1]; L[0][0] = 0; a[0] = -INF; int S[LOGM][n+1]; S[0][0] = 0;
for(int i = 1; i <= n; i++)
{
L[0][i] = i-1;
while(a[L[0][i]] >= a[i])
L[0][i] = L[0][L[0][i]];
S[0][i] = a[i]*(i-L[0][i]);
}
for(int i = 1; i < LOGM; i++)
{
for(int j = 0; j <= n; j++)
{
L[i][j] = L[i-1][L[i-1][j]];
S[i][j] = S[i-1][j]+S[i-1][L[i-1][j]];
}
}
int q; cin >> q;
while(q--)
{
int l, r;
cin >> l >> r;
int SS = pref[r]-pref[l-1];
for(int i = LOGM-1; i >= 0; i--)
{
if(L[i][r] >= l)
{
SS-=S[i][r];
r = L[i][r];
}
}
SS-=(a[r]*(r-l+1));
if(a[r] < (-off[l]))
SS = -1;
cout << SS << "\n";
}
return 0;
}
