// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
using namespace std;
#define int long long
#define endl "\n"
#define fi first
#define se second
const int M=998244353;
const int inf = 1e14;
const int LOG=20;
const int N=3e5+5;
int n , m , c , w , k , t=1 , q=1 , x , y , z , l , r;
struct node{
int mx=0,sm=0,mn=inf;
};
node join(node x,node y){
node r;
r.mx=max(x.mx,y.mx);
r.mn=min(x.mn,y.mn);
r.sm=x.sm+y.sm;
return r;
}
node seg[4*N];
int a[N],b[N],vi[N],di[N];
void build(int s=1,int e=n+1,int v=1){
if (e-s==1){
seg[v].mx=vi[s];
seg[v].sm=di[s];
seg[v].mn=di[s];
return;
}
int li=2*v;
int ri=2*v+1;
int m=(s+e)/2;
build(s,m,li);
build(m,e,ri);
seg[v]=join(seg[li],seg[ri]);
}
node query(int l,int r,int s=1,int e=n+1,int v=1){
if (l<=s and e<=r){
return seg[v];
}
if (r<=s or l>=e){
node p;
return p;
}
int li=2*v;
int ri=2*v+1;
int m=(s+e)/2;
return join(query(l,r,s,m,li),query(l,r,m,e,ri));
}
void solve()
{
cin >> n >> x;
for (int i=1;i<=n;i++){
cin >> a[i];
b[i]=a[i]-(a[i]/x)*x;
int u=max(0ll,(b[i-1]-b[i]+x-1)/x);
b[i]+=u*x;
di[i]=a[i]-b[i];
if (b[i]>a[i]){
vi[i]=1;
}
}
build();
cin >> q;
for (int o=0;o<q;o++){
cin >> l >> r;
if (query(l+1,r+1).mx){
cout << -1 << endl;
continue;
}
node p=query(l,r+1);
cout << (p.sm-p.mn*(r-l+1))/x << endl;
}
}
signed main()
{
ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE
cin.tie(0), cout.tie(0);//DO NOT USE IN INTERACTIVE
cout << fixed << setprecision(9);
// int t=1;
// cin >> t;
for (int _=1;_<=t;_++){
solve();
q++;
}
}
