#include <bits/stdc++.h>
#define int long long
using namespace std;
#define L(i, j, k) for(int i = (j); i <= (k); ++i)
#define R(i, j, k) for(int i = (j); i >= (k); --i)
std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
int INF=1e18;
int LG=19;
void solve() {
int n,m;cin>>n>>m;
INF=(INF/m)*m;
vector<int> arr(n);
vector<int> og;
vector<int> pref(n);
L(i,0,n-1){
cin>>arr[i];
}
og=arr;
int at=0;
L(i,0,n-1){
arr[i]-=at;
at+=((INF+arr[i])%m);
arr[i]-=(INF+arr[i])%m;
arr[i]/=m;
}
L(i,0,n-1){
pref[i]=arr[i];
if(i!=0)pref[i]+=pref[i-1];
//cout<<arr[i]<<" ";
}
//cout<<"\n";
vector<int> st;
int dp[LG][n];
int val[LG][n];
L(i,0,n-1){
while(!st.empty() && arr[st.back()]>=arr[i]){
st.pop_back();
}
dp[0][i]=(st.empty()?i:st.back());
st.push_back(i);
}
L(i,0,n-1){
int v=dp[0][i];
//cout<<v<<" ";
val[0][i]=pref[i]-pref[v]-arr[i]*(i-v);
//cout<<val[0][i]<<"\n";
}
L(pot,1,LG-1){
L(i,0,n-1){
dp[pot][i]=dp[pot-1][dp[pot-1][i]];
val[pot][i]=val[pot-1][i]+val[pot-1][dp[pot-1][i]];
}
}
int q;cin>>q;
while(q--){
int l,r;cin>>l>>r;
l--;r--;
int at=r;
int resp=0;
R(pot,LG-1,0){
if(dp[pot][at]>=l){
resp+=val[pot][at];
at=dp[pot][at];
}
}
int pp=0;
if(l!=0)pp=pref[l-1];
if((arr[l]-arr[at])*m>og[l]){
cout<<-1<<"\n";
}
else{
resp+=pref[at]-pp-arr[at]*(at-l+1);
cout<<resp<<"\n";
}
}
}
int32_t main() {
std::cin.tie(0)->sync_with_stdio(0);
std::cin.exceptions(std::cin.failbit);
int T = 1;
// std::cin >> T;
while(T--) {
solve();
}
return 0;
}
