#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ii pair<int,int>
#define iii tuple<int,int,int>
#define fi first
#define se second
#define endl '\n'
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define lb lower_bound
#define ub upper_bound
#define rep(x,start,end) for(int x=(start)-((start)>(end));x!=(end)-((start)>(end));((start)<(end)?x++:x--))
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
int n,k,q;
int arr[300005];
int brr[300005];
int pref1[300005];
int pref2[300005];
ii nxt[300005][20];
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin.exceptions(ios::badbit | ios::failbit);
cin>>n>>k;
rep(x,1,n+1) cin>>arr[x];
rep(x,1,n+1) brr[x]=arr[x-1]-arr[x];
int L=1e18/k;
rep(x,1,n+1) brr[x]+=(-brr[x]+k*L)%k;
rep(x,1,n+1) pref1[x]=pref1[x-1]+brr[x];
rep(x,1,n+1) pref2[x]=pref2[x-1]+brr[x]*x;
int P=0;
vector<ii> v={{4e18,0}};
rep(x,1,n+1){
P+=brr[x];
while (!v.empty() && v.back().fi<P) v.pob();
int y=v.back().se;
nxt[x][0]={y,(pref2[x]-pref2[y+1])-(pref1[x]-pref1[y+1])*(y+1)};
v.pub({P,x});
}
rep(y,1,20) rep(x,1,n+1){
int u=nxt[x][y-1].fi;
nxt[x][y]={
nxt[u][y-1].fi,
nxt[x][y-1].se+nxt[u][y-1].se
};
}
cin>>q;
while (q--){
int l,r; cin>>l>>r;
int ans=0;
rep(x,20,0) if (nxt[r][x].fi>=l){
ans+=nxt[r][x].se;
r=nxt[r][x].fi;
}
ans+=(pref2[r]-pref2[l])-(pref1[r]-pref1[l])*(l);
int v=arr[l]-(pref1[r]-pref1[l]);
if (v<0) cout<<"-1"<<endl;
else cout<<ans/k<<endl;
}
}
