#include <bits/stdc++.h>
using namespace std;
#define int long long
#define f first
#define s second
#define pll pair<int,int>
#define pb push_back
#define g0(x) get<0>(x)
#define g1(x) get<1>(x)
#define g2(x) get<2>(x)
#define ld long double
struct node {
int s, e, m, v, lz;
node *l, *r;
node (int S, int E){
s=S, e=E, m=(s+e)/2, v=0, lz=0;
if(s!=e){
l=new node(s, m);
r=new node(m+1, e);
}
}
void prop(){
if(s==e or lz==0)return;
l->v+=(l->e - l->s +1) * lz, r->v+=(r->e-r->s+1)*lz, l->lz+=lz, r->lz+=lz;
lz=0;
}
int combine(int a, int b){
return a+b;
}
void upd(int S, int E, int V){
if((S==s and E==e) or s==e){
v+=(e-s+1) * V;
lz+=V;
return;
}
prop();
if (E<=m) l->upd(S,E,V);
else if (S>m) r->upd(S,E,V);
else l->upd(S,m,V),r->upd(m+1,E,V);
v=combine(l->v,r->v);
}
int qry(int S,int E){
if((S==s and E==e) or s==e){
return v;
}
prop();
if(E<=m)return l->qry(S,E);
if(S>m)return r->qry(S,E);
return combine(l->qry(S,m),r->qry(m+1,E));
}
} *root;
int n,d;
int c[300005];
int ans[300005];
int qq;
int val(int x){
return c[x] - d * root->qry(x, x);
}
signed main(){
cin>>n>>d;
for(int i=1;i<=n;i++){
cin>>c[i];
}
root=new node(0,n);
//~ root=new node(0,5);
//~ root->upd(2, 3, 5);
//~ root->upd(1, 5, 5);
//~ cout<<root->qry(0,5);
//~ return 0;
c[0]=LLONG_MIN;
vector<pair<int,int>> q;
q.push_back({0,0});
cin>>qq;
vector<tuple<int,int,int>> qs;
for(int i=0;i<qq;i++){
int l,r;cin>>l>>r;
qs.push_back({r,l,i});
}
sort(qs.begin(),qs.end());
int qptr=0;
for(int i=1;i<=n;i++){
//~ cout<<"start of " << i <<endl;
//~ for (auto it : q){
//~ printf("| %lld, %lld to %lld, %lld |", it.f, val(it.f), it.s, val(it.s));
//~ cout<<endl;
//~ }
int bk, cc;
cc=c[i], bk=val(q.back().s);
while(bk > cc){
int mvs=(bk-cc)/d + ((bk-cc)%d?1:0);
//~ printf("moves needed is %lld\n", mvs);
root->upd(q.back().f, q.back().s, mvs);
cc=val(q.back().f);
//~ printf("cc is now %lld\n", cc);
q.pop_back();
bk=val(q.back().s);
}
q.push_back({q.back().s+1, i});
while(qptr < qq and g0(qs[qptr])==i){
auto [r, l, ansind] = qs[qptr];
int fv = val(l);
if (fv < 0) ans[ansind]=-1;
else ans[ansind]=root->qry(l, r);
qptr++;
}
//~ cout<<"end of " << i <<endl;
//~ for (auto it : q){
//~ printf("| %lld, %lld to %lld, %lld |", it.f, val(it.f), it.s, val(it.s));
//~ cout<<endl;
//~ }
//~ for(int j=1;j<=n;j++){
//~ cout<<root->qry(j,j)<<" ";
//~ }
//~ cout<<endl;
}
for(int i=0;i<qq;i++){
cout<<ans[i]<<"\n";
}
}
/*
4 2
0 1 0 1
2
1 2
1 4
*/
