#include <bits/stdc++.h>
#define int long long
using namespace std;
int z[10000005];
int t[10000005];
vector <pair<int,int>> q[1000005];
int prefix[1000005];
int inf=-1e12;
int res[1000005];
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int a,d;
cin >> a >> d;
for (int i=1;i<=a;i++){
cin >> z[i];
}
int c;
cin >> c;
for (int i=1;i<=c;i++){
int x,y;
cin >> x >> y;
q[y].push_back({x,i});
}
for (int i=a-1;i>=1;i--){
if (z[i]>=z[i+1]){
t[i]=t[i+1]+(z[i]-z[i+1]+d-1)/d;
}else{
t[i]=t[i+1]-(z[i+1]-z[i])/d;
}
}
for (int i=1;i<=a;i++){
prefix[i]=prefix[i-1]+t[i];
}
vector <pair<int,int>> st;
st.push_back({-1*1LL,0LL});
for (int i=1;i<=a;i++){
while (st.size()>1 && t[st.back().first]>=t[i]){
st.pop_back();
}
st.push_back({i,st.back().second+(i-st.back().first)*t[i]});
for (auto p:q[i]){
int pos=lower_bound(st.begin(),st.end(),make_pair(p.first,inf))-st.begin();
int pre=st.back().second-st[pos-1].second-t[st[pos].first]*(p.first-1-st[pos-1].first);
res[p.second]=prefix[i]-prefix[p.first-1]-pre;
if (z[p.first]<d*(t[p.first]-t[st[pos].first])){
res[p.second]=-1;
}
}
// cerr << i << "\n";
}
for (int i=1;i<=c;i++){
cout << res[i] << "\n";
}
return 0;
}
