# include <bits/stdc++.h>
using namespace std;
#define int long long
const int maxN = 5e5 + 5;
int n, D, q;
int a[maxN];
vector <array <int, 2>> off[maxN];
long long ans[maxN];
struct SegmentTree {
long long st[4 * maxN], lazy[4 * maxN];
void apply(int id, long long val, int l, int r) {
st[id]+= 1LL * (r - l + 1) * val;
lazy[id]+= val;
}
void pushDown(int id, int l, int r) {
if (lazy[id]) {
apply(id << 1, lazy[id], l, (l + r) / 2);
apply(id << 1 | 1, lazy[id], (l + r) / 2 + 1, r);
lazy[id] = 0;
}
}
void update(int id, int l, int r, int u, int v, int val) {
if (l > v || r < u) return;
if (l >= u && r <= v) {
apply(id, val, l, r);
return;
}
int mid = (l + r) >> 1;
pushDown(id, l, r);
update(id << 1, l, mid, u, v, val);
update(id << 1 | 1, mid + 1, r, u, v, val);
st[id] = st[id << 1] + st[id << 1 | 1];
}
long long get(int id, int l, int r, int u, int v) {
if (l > v || r < u) return 0;
if (l >= u && r <= v) return st[id];
pushDown(id, l, r);
int mid = (l + r) >> 1;
return get(id << 1, l, mid, u, v) + get(id << 1 | 1, mid + 1, r, u, v);
}
} ST;
signed main () {
ios_base :: sync_with_stdio(0); cin.tie(0);
freopen("kieuoanh.inp", "r", stdin);
freopen("kieuoanh.out", "w", stdout);
cin >> n >> D;
for (int i = 1; i <= n; i++) {
cin >> a[i];
}
cin >> q;
for (int i = 1; i <= q; i++) {
int l, r; cin >> l >> r;
off[r].push_back({l, i});
}
stack <int> st;
for (int i = 1; i <= n; i++) {
int cur = i;
while (!st.empty()) {
int x = a[cur - 1] - ST.get(1, 1, n, cur - 1, cur - 1) * D;
int y = a[cur] - ST.get(1, 1, n, cur, cur) * D;
if (x <= y) break;
int need = (x - y - 1) / D + 1;
ST.update(1, 1, n, st.top(), cur - 1, need);
cur = st.top();
st.pop();
}
st.push(cur);
for (auto x : off[i]) {
int l = x[0], id = x[1];
if (a[l] - ST.get(1, 1, n, l, l) * D < 0) {
ans[id] = - 1;
} else {
ans[id] = ST.get(1, 1, n, l, i);
}
}
}
for (int i = 1; i <= q; i++) {
cout << ans[i] << "\n";
}
return 0;
}
