#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n,d;
cin >> n >> d;
int c[n];
for(int &i : c){
cin >> i;
}
const int lg = 20;
const int inf = 1e18;
int lef[n][lg];
int ans[n][lg];
map<int,int>mp;
mp[-1]=-1;
int las = 0;
int pref[n];
ans[0][0]=0;
pref[0]=c[0];
lef[0][0]=-1;
for(int i = 1;i<n;i++){
auto it = mp.upper_bound(c[i]);
--it;
lef[i][0]=(*it).second;
pref[i]=c[i];
if(i){
pref[i]+=pref[i-1];
}
if(las<=(*it).second+1){
int sum = 0;
if(i){
sum=pref[i-1];
}
if((*it).second>=0)
sum-=pref[(*it).second];
int req = c[las]%d;
if(req>c[i]){
ans[i][0]=inf;
}
else{
req=((c[i]-req)/d)*d+req;
sum-=(i-(*it).second-1)*req;
assert(sum%d==0);
ans[i][0]=sum/d;
}
}
else{
ans[i][0]=inf;
}
if(c[las]%d!=c[i]%d){
las=i;
}
mp[c[i]]=i;
}
for(int i = 0;i<n;i++){
fill(lef[i]+1,lef[i]+lg,-1);
fill(ans[i]+1,ans[i]+lg,inf);
for(int j = 1;j<lg;j++){
if(lef[i][j-1]<0)
break;
lef[i][j]=lef[lef[i][j-1]][j-1];
ans[i][j]=ans[i][j-1]+ans[lef[i][j-1]][j-1];
}
}
int q;
cin >> q;
while(q--){
int l,r;
cin >> l >> r;
l--;r--;
int curr = 0;
for(int i = lg-1;i>=0;i--){
if(lef[r][i]>=l){
//valid
curr+=ans[r][i];
r=lef[r][i];
}
}
assert(lef[r][0]<l);
int m = c[r-1]%d;
for(int i = r-1;i>=l;i--){
if(c[i]%d!=m){
curr=inf;
break;
}
if(m>c[r]){
curr=inf;
break;
}
int req=((c[r]-m)/d)*d+m;
assert((c[i]-req)%d==0);
if(c[i]-req<0){
curr=inf;
break;
}
curr+=(c[i]-req)/d;
}
if(curr>=inf){
cout << -1 << "\n";
}
else{
cout << curr << "\n";
}
}
return 0;
}
