#include <bits/stdc++.h>
#define int long long
using namespace std;
const long long N = 3e5 + 5;
int a[N];
int original_A[N];
int b[N];
int c[N]; // count of zeros
int p[N]; // prefix sm
const int lg = 19;
int sp[N][lg];
// Function to initialize the Sparse Table
void initialize(int n, int ls[])
{
for (int i = 0; i < n; i++)
{
sp[i][0] = ls[i];
}
for (int i = 1; i < lg; i++)
{
for (int j = 0; j + (1ll << i) <= n; j++)
{
sp[j][i] = min(sp[j][i - 1], sp[j + (1ll << (i - 1))][i - 1]);
}
}
}
// Function to get the minimum value in the range [l, r]
int get(int l, int r)
{
int ch = 31 - __builtin_clz(r - l + 1);
return min(sp[l][ch], sp[r - (1ll << ch) + 1][ch]);
}
void solve()
{
int n, d;
cin >> n >> d;
for (int i = 1; i <= n; i++)
{
cin >> a[i];
original_A[i] = a[i];
}
for (int i = n; i > 1; i--)
{
int k = (a[i - 1] - a[i] + d - 1) / d;
k = max(k, 0ll);
b[i - 1] = k;
a[i - 1] -= d * k;
}
initialize(n + 1, b);
for (int i = 1; i <= n; i++)
{
c[i + 1] = c[i] + (b[i] == 0);
p[i] = p[i - 1] + b[i];
}
// for (int i = 0; i <= n; i++)
// {
// cout << a[i] << " ";
// }
// cout << endl;
// for (int i = 0; i <= n; i++)
// {
// cout << b[i] << " ";
// }
// cout << endl;
// for (int i = 0; i <= n; i++)
// {
// cout << c[i] << " ";
// }
// cout << endl;
// for (int i = 0; i <= n; i++)
// {
// cout << p[i] << " ";
// }
// cout << endl;
int q;
cin >> q;
int mn, mx;
for (int i = 0; i < q; i++)
{
cin >> mn >> mx;
int l = mn - 1, r = mx + 1;
while (r - l > 1)
{
int mid = (r + l) / 2;
(c[mid] < c[mx]) ? (l = mid) : (r = mid);
}
{
r = min(r, mx);
int k = get(r, mx);
if (original_A[mn] - (b[mn] - (r == mn) * k) * d < 0)
{
cout << -1 << endl;
continue;
}
if (original_A[r] - (b[r] - k) * d < 0)
{
cout << -1 << endl;
continue;
}
cout << p[mx - 1] - p[mn - 1] - k * (mx - (r));
// cout << endl;
// cout << p[mx - 1] - p[mn - 1] << " " << k * (mx - (r));
}
cout << endl;
}
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
int t = 1;
// cin >> t;
while (t--)
{
solve();
cout << endl;
}
return 0;
}
