//chockolateman
#include<bits/stdc++.h>
using namespace std;
const long long INF = 1e15;
int N,Q,p[300005],s[300005],starts[300005];
long long D,a[300005],ans[300005],st[1200005],lazy[1200005];
pair<pair<int,int>,int> queries[300005];
void propagate(int v,int start,int end);
void update(int l,int r,long long val,int v = 1,int start = 1,int end = N)
{
if(start==l && end==r)
{
st[v] += val * (end - start + 1);
lazy[v] += val;
return;
}
propagate(v,start,end);
int mid = (start + end)/2;
if(r <= mid)
update(l,r,val,2*v,start,mid);
else if(l > mid)
update(l,r,val,2*v+1,mid+1,end);
else
{
update(l,mid,val,2*v,start,mid);
update(mid+1,r,val,2*v+1,mid+1,end);
}
st[v] = st[2*v] + st[2*v+1];
}
void propagate(int v,int start,int end)
{
if(lazy[v])
{
int mid = (start + end)/2;
update(start,mid,lazy[v],2*v,start,mid);
update(mid+1,end,lazy[v],2*v+1,mid+1,end);
lazy[v] = 0;
}
}
long long query(int l,int r,int v = 1,int start = 1,int end = N)
{
if(start==l && end==r)
return st[v];
propagate(v,start,end);
int mid = (start + end)/2;
if(r <= mid)
return query(l,r,2*v,start,mid);
else if(l > mid)
return query(l,r,2*v+1,mid+1,end);
else
return query(l,mid,2*v,start,mid) + query(mid+1,r,2*v+1,mid+1,end);
}
int find_Sett(int i)
{
if(p[i]==i)
return i;
p[i] = find_Sett(p[i]);
return p[i];
}
bool is_Same_Sett(int i,int j)
{
return find_Sett(i) == find_Sett(j);
}
int get_start(int i)
{
return starts[find_Sett(i)];
}
void union_Sett(int i,int j)
{
if(is_Same_Sett(i,j))
return;
int x = find_Sett(i);
int y = find_Sett(j);
if(s[x] < s[y])
swap(x,y);
p[y] = x;
s[x] += s[y];
starts[x] = min(starts[x],starts[y]);
}
int main()
{
scanf("%d%lld",&N,&D);
for(int i = 1 ; i <= N ; i++)
scanf("%lld",&a[i]);
for(int i = 1 ; i <= N ; i++)
{
p[i] = i;
s[i] = 1;
starts[i] = i;
}
scanf("%d",&Q);
for(int l,r,i = 1 ; i <= Q ; i++)
{
scanf("%d%d",&l,&r);
queries[i] = {{r,l},i};
}
sort(queries+1,queries+Q+1);
int pos = 0;
for(int l,r,indx,i = 1 ; i <= Q ; i++)
{
l = queries[i].first.second;
r = queries[i].first.first;
indx = queries[i].second;
//process
while(pos < r)
{
pos++;
while(get_start(pos) > 1 && a[get_start(pos)] - query(get_start(pos),get_start(pos))*D < a[get_start(pos)-1] - query(get_start(pos)-1,get_start(pos)-1)*D)
{
long long lim = a[get_start(pos)] - query(get_start(pos),get_start(pos))*D;
long long cur_val = a[get_start(pos)-1] - query(get_start(pos)-1,get_start(pos)-1)*D;
long long targ = (lim/D)*D + cur_val%D;
if(targ > lim)
targ -= D;
long long red = (cur_val - targ)/D;
update(get_start(get_start(pos)-1),get_start(pos)-1,red);
union_Sett(get_start(pos)-1,pos);
}
}
if(a[l] - query(l,l)*D < 0)
ans[indx] = -1;
else
ans[indx] = query(l,r);
}
for(int i = 1 ; i <= Q ; i++)
printf("%lld\n",ans[i]);
return 0;
}
