#include <bits/stdc++.h>
using namespace std;
using ll = long long; using pii = pair<ll,ll>;
const ll Nm = 524288; const ll E = 19;
ll rmqv[Nm][E+1];
void initRMQ(vector<ll> b) {
ll N = b.size();
for (ll i=0;i<N;i++) {
rmqv[i][0]=b[i];
}
for (ll j=1;j<=E;j++) {
for (ll i=0;i<(N-(1LL<<j)+1);i++) {
rmqv[i][j]=min(rmqv[i][j-1],rmqv[i+(1LL<<(j-1))][j-1]);
}
}
}
ll l2(ll x) {
return (31-__builtin_clz(x));
}
ll rmq(ll a, ll b) {
ll l = l2(b-a+1);
return min(rmqv[a][l],rmqv[b-(1LL<<l)+1][l]);
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0);
ll N,D; cin >> N >> D;
ll c[N]; ll rem[N]; ll d0[N]; ll a[N]; vector<ll> b;
for (ll i=0;i<N;i++) {
cin >> c[i];
rem[i]=c[i]%D;
d0[i]=c[i]/D;
}
a[0]=0;
b.push_back(d0[0]);
for (ll i=1;i<N;i++) {
if (rem[i-1]>rem[i]) {
a[i]=a[i-1]+1;
} else {
a[i]=a[i-1];
}
b.push_back(d0[i]-a[i]);
}
ll psb[N+1];
psb[0]=0;
for (ll i=0;i<N;i++) {
psb[i+1]=psb[i]+b[i];
}
initRMQ(b);
ll Q; cin >> Q;
ll ans[Q];
vector<pii> qr[N]; //qr[right]={left,qryIndex}
for (ll q=0;q<Q;q++) {
ll l,r; cin >> l >> r;
l--; r--;
qr[r].push_back({l,q});
}
vector<pii> cnums; //{value,x-coord}
//in strictly INCREASING order
for (ll r=0;r<N;r++) {
while (!cnums.empty()) {
ll vb = cnums.back().first;
if (vb>=b[r]) {
cnums.pop_back();
} else {
break;
}
}
cnums.push_back({b[r],r});
for (pii qrn: qr[r]) {
ll l = qrn.first; ll q = qrn.second;
if (rmq(l,r)<(-a[l])) {
ans[q]=-1; continue;
}
ll vf = 0;
for (ll i=l;i<=r;i++) {
vf += (b[i]-rmq(i,r));
}
ans[q]=vf;
}
}
for (ll q=0;q<Q;q++) {
cout << ans[q]<<"\n";
}
}
