#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MASK(x) (1LL << (x))
#define BIT(x, i) (((x) >> (i)) & 1)
#define SZ(x) ((int) (x).size())
#define ALL(a) (a).begin(), (a).end()
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define REP(i, n) for (int i = 0, _n = (n); i < _n; ++i)
#define left __left
#define right __right
#define prev __prev
#define next __next
template <class X, class Y>
bool maximize(X &x, Y y) {
if (x < y) return x = y, true;
else return false;
}
template <class X, class Y>
bool minimize(X &x, Y y) {
if (x > y) return x = y, true;
else return false;
}
struct Check {
int id, cost;
friend istream& operator >> (istream& in, Check &c) {
in >> c.id >> c.cost;
return in;
}
bool operator < (const Check &other) const {
return (cost < other.cost);
}
};
struct Query {
int s, t;
ll gold, silver;
friend istream& operator >> (istream& in, Query &q) {
in >> q.s >> q.t >> q.gold >> q.silver;
return in;
}
};
struct Edge {
int u, v;
};
const int LOG = 17;
#define MAX_N 100100
int numNode, M, q;
int timeDFS = 0;
vector<int> adj[MAX_N + 2];
int sta[MAX_N + 2], fin[MAX_N + 2];
int par[LOG + 2][MAX_N + 2];
Edge edges[MAX_N + 2];
Check chk[MAX_N + 2];
Query query[MAX_N + 2];
int Lca[MAX_N + 2], cntQuery[MAX_N + 2], res[MAX_N + 2];
int L[MAX_N + 2], R[MAX_N + 2], G[MAX_N + 2];
struct BIT {
ll bit[MAX_N + 2];
int cnt[MAX_N + 2];
int n;
void init(int _n) {
n = _n;
memset(bit, 0, (_n + 2) * sizeof(ll));
memset(cnt, 0, (_n + 2) * sizeof(int));
}
void update(int x, int v) {
for (; x <= n; x += x & (-x)) {
bit[x] += v;
cnt[x] += (v > 0 ? 1 : -1);
}
}
void updateRange(int l, int r, int v) {
update(l, v);
update(r + 1, -v);
}
int getCnt(int x) {
int ans = 0;
for (; x > 0; x -= x & (-x)) ans += cnt[x];
return ans;
}
ll get(int x) {
ll ans = 0;
for (; x > 0; x -= x & (-x)) ans += bit[x];
return ans;
}
} fen;
void dfs(int u) {
sta[u] = ++timeDFS;
for (int v : adj[u]) {
if (v == par[0][u]) continue;
par[0][v] = u;
FOR(j, 1, LOG) par[j][v] = par[j - 1][par[j - 1][v]];
dfs(v);
}
fin[u] = timeDFS;
}
bool inSubtree(int u, int v) {
return (sta[u] <= sta[v] && fin[v] <= fin[u]);
}
int lca(int u, int v) {
if (inSubtree(u, v)) return u;
if (inSubtree(v, u)) return v;
FORD(i, LOG, 0) if (par[i][u] != 0 && !inSubtree(par[i][u], v)) u = par[i][u];
return par[0][u];
}
bool cmp(const int &x, const int &y) {
return (G[x] < G[y]);
}
int main() {
ios_base::sync_with_stdio(false);cin.tie(nullptr);
cin >> numNode >> M >> q;
FOR(i, 1, numNode - 1) {
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
edges[i] = {u, v};
}
FOR(i, 1, M) cin >> chk[i];
FOR(i, 1, q) cin >> query[i];
sort(chk + 1, chk + 1 + M);
dfs(1);
FOR(i, 1, numNode - 1) {
if (sta[edges[i].u] > sta[edges[i].v]) swap(edges[i].u, edges[i].v);
}
FOR(i, 1, q) L[i] = 0, R[i] = M;
FOR(i, 1, q) Lca[i] = lca(query[i].s, query[i].t);
fen.init(numNode);
FOR(i, 1, M) {
int id = chk[i].id;
int v = edges[id].v;
fen.updateRange(sta[v], fin[v], 1);
}
FOR(i, 1, q) {
int u = query[i].s, v = query[i].t;
cntQuery[i] = fen.getCnt(sta[u]) + fen.getCnt(sta[v]) - 2 * fen.getCnt(sta[Lca[i]]);
res[i] = -1;
}
while (true) {
vector<int> checks;
FOR(i, 1, q) if (L[i] <= R[i]) G[i] = (L[i] + R[i]) >> 1, checks.push_back(i);
if (checks.empty()) break;
sort(ALL(checks), cmp);
fen.init(numNode);
int ptr = 1;
for (int id : checks) {
while (ptr <= G[id]) {
int idEdge = chk[ptr].id;
int v = edges[idEdge].v;
fen.updateRange(sta[v], fin[v], chk[ptr].cost);
++ptr;
}
/// getResults;
int u = sta[query[id].s], v = sta[query[id].t], r = sta[Lca[id]];
ll totalVal = fen.get(u) + fen.get(v) - 2 * fen.get(r);
int totalCnt = fen.getCnt(u) + fen.getCnt(v) - 2 * fen.getCnt(r);
if (totalVal <= query[id].silver) {
L[id] = G[id] + 1;
if (cntQuery[id] - totalCnt <= query[id].gold) {
res[id] = query[id].gold - (cntQuery[id] - totalCnt);
}
} else R[id] = G[id] - 1;
}
}
FOR(i, 1, q) cout << res[i] << "\n";
return 0;
}
