#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb push_back
const int N = 1e5 + 5, LOG = 17;
struct HLD {
vector<int> g[N];
int D[N], up[LOG][N], sz[N], pr[N], id[N], C = 0;
ll a[N];
struct BIT {
int n;
vector<ll> b;
void init(int _n) {
if (n > _n) return;
b.resize(_n, 0);
n = _n;
}
void reset() {
fill(b.begin(), b.end(), 0);
}
void add(int p, int x) {
for (; p < n; p |= (p + 1)) b[p] += x;
}
ll sum(int r) {
ll S = 0;
for (; r >= 0; r = (r & (r + 1)) - 1) S += b[r];
return S;
}
ll sum(int l, int r) {
return sum(r) - (l > 0 ? sum(l-1) : 0);
}
} ch[N];
void dfs(int s, int e = -1) {
sz[s] = 1;
for (auto u : g[s]) {
if (u == e) continue;
D[u] = D[s] + 1, up[0][u] = s;
dfs(u, s);
sz[s] += sz[u];
}
for (auto u : g[s]) {
if (u == e) continue;
if (sz[u] > sz[s] / 2) pr[id[u]] = s, id[s] = id[u];
}
if (!id[s]) {
id[s] = ++C;
pr[id[s]] = s;
}
}
void dfs2(int s, int e = -1) {
if (e != -1 && id[s] != id[e]) ch[id[e]].init(D[e] - D[pr[id[e]]] + 1);
if (e != -1 && g[s].size() == 1) ch[id[s]].init(D[s] - D[pr[id[s]]] + 1);
for (auto u : g[s]) {
if (u == e) continue;
dfs2(u, s);
}
}
void init() {
dfs(1);
dfs2(1);
for (int i = 1; i < LOG; ++i) {
for (int j = 1; j < N; ++j) {
up[i][j] = up[i-1][up[i-1][j]];
}
}
}
void reset() {
for (int i = 0; i < N; ++i) ch[i].reset();
fill(a, a+N, 0);
}
int jump(int u, int k) {
for (int i = LOG-1; i >= 0; --i) {
if ((k >> i) & 1) u = up[i][u];
}
return u;
}
int lca(int u, int v) {
if (D[u] < D[v]) swap(u, v);
u = jump(u, D[u] - D[v]);
if (u == v) return u;
for (int i = LOG-1; i >= 0; --i) {
if (up[i][u] != up[i][v]) u = up[i][u], v = up[i][v];
}
return up[0][u];
}
void add(int u, int v, ll x) {
if (D[u] < D[v]) swap(u, v);
if (id[u] != id[v]) a[u] += x;
else {
ch[id[u]].add(D[u] - D[pr[id[u]]], x);
}
}
ll sum(int u, int v) {
ll S = 0;
while (D[u] > D[v]) {
if (id[u] == id[v]) S += ch[id[u]].sum(D[v] - D[pr[id[u]]] + 1, D[u] - D[pr[id[u]]]);
else {
S += ch[id[u]].sum(0, D[u] - D[pr[id[u]]]);
}
u = pr[id[u]]; if (D[u] <= D[v]) break;
S += a[u]; u = up[0][u];
}
return S;
}
ll calc(int u, int v) {
int L = lca(u, v);
if (D[u] < D[v]) swap(u, v);
return sum(u, L) + sum(v, L);
}
} T;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n, m, q;
cin >> n >> m >> q;
array<int, 2> E[n];
for (int i = 1; i < n; ++i) {
int u, v;
cin >> u >> v;
T.g[u].pb(v); T.g[v].pb(u);
E[i] = {u, v};
}
array<int, 2> e[m+1];
for (int i = 1; i <= m; ++i) cin >> e[i][1] >> e[i][0];
sort(e+1, e+m+1);
for (int i = 1; i <= m; ++i) swap(e[i][0], e[i][1]);
array<int, 4> qu[q+1];
for (int i = 1; i <= q; ++i) cin >> qu[i][0] >> qu[i][1] >> qu[i][2] >> qu[i][3];
int L[q+1], R[q+1], P[q+1];
fill(L, L+q+1, 0); fill(R, R+q+1, m); fill(P, P+q+1, 0);
T.init();
// for (int i = 1; i <= m; ++i) {
// cout << E[e[i][0]][0] << ' ' << E[e[i][0]][1] << ' ' << e[i][1] << '\n';
// T.add(E[e[i][0]][0], E[e[i][0]][1], e[i][1]);
// cout << T.calc(qu[1][0], qu[1][1]) << '\n';
// }
for (int _ = 0; _ < LOG; ++_) {
vector<int> B[m+1];
T.reset();
for (int i = 1; i <= q; ++i) {
if (L[i] <= R[i]) {
B[(L[i] + R[i]) / 2].pb(i);
}
}
for (int i = 0; i <= m; ++i) {
if (i) T.add(E[e[i][0]][0], E[e[i][0]][1], e[i][1]);
for (auto j : B[i]) {
if (T.calc(qu[j][0], qu[j][1]) <= qu[j][3]) P[j] = i, L[j] = i+1;
else {
R[j] = i-1;
}
}
}
}
T.reset();
vector<int> B[m+1];
for (int i = 1; i <= q; ++i) B[P[i]].pb(i);
for (int i = 0; i <= m; ++i) {
if (i) T.add(E[e[i][0]][0], E[e[i][0]][1], 1);
for (auto j : B[i]) {
qu[j][2] += T.calc(qu[j][0], qu[j][1]);
}
}
for (int i = 1; i <= q; ++i) {
cout << max(-1LL, qu[i][2] - T.calc(qu[i][0], qu[i][1])) << '\n';
}
}
