#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0);
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define pb push_back
#define eb emplace_back
#define f first
#define s second
#define int long long
#define lowbit(x) x&-x
const int maxn = 1e5 + 5;
const int INF = 1e9 + 7;
vector<int> adj[maxn];
pll road[maxn];
int sz[maxn], dep[maxn], id[maxn], loc[maxn], par[maxn];
int in[maxn], out[maxn];
int head[maxn];
int cnt = 0, dfn = 0;
int n, m, q;
pll operator + (pll a, pll b){
return pll(a.f + b.f, a.s + b.s);
}
pll operator - (pll a, pll b){
return pll(a.f - b.f, a.s - b.s);
}
void operator += (pll &a, pll b){
a.f += b.f, a.s += b.s;
}
struct BITree{
pll BIT[maxn * 2];
void upd(int pos, pll val){
while(pos < maxn * 2){
BIT[pos] += val;
pos += lowbit(pos);
}
}
pll qry(int pos){
pll ret = {0, 0};
while(pos > 0){
ret += BIT[pos];
pos -= lowbit(pos);
}
return ret;
}
} st;
void dfs(int pos, int prev){
if(prev != -1) adj[pos].erase(find(adj[pos].begin(), adj[pos].end(), prev));
in[pos] = ++dfn;
sz[pos] = 1;
for(auto &x : adj[pos]){
dep[x] = dep[pos] + 1;
par[x] = pos;
dfs(x, pos);
if(sz[x] > sz[adj[pos][0]]) swap(x, adj[pos][0]);
}
out[pos] = ++dfn;
}
void decompose(int pos, int h){
head[pos] = h;
// id[pos] = ++cnt, loc[cnt] = pos;
for(auto x : adj[pos]){
if(x == adj[pos][0]) decompose(x, h);
else decompose(x, x);
}
}
struct info{
int s, t, x, y, id;
info(){}
info(int _s, int _t, int _x, int _y, int _id) : s(_s), t(_t), x(_x), y(_y), id(_id){}
};
int lca(int a, int b){
while(head[a] != head[b]){
if(dep[head[a]] > dep[head[b]]) swap(a, b);
b = par[head[b]];
}
if(dep[a] > dep[b]) swap(a, b);
return a;
}
pll solve(int s, int t){
int lc = lca(s, t);
return st.qry(in[s]) + st.qry(in[t]) - st.qry(in[lc]) - st.qry(in[lc]);
}
pll lok[maxn]; // 剛好可以 max. amount of gold coins
pll bad[maxn]; // 剛好不行
void bs(vector<pll> a, vector<info> rng, int l, int r){
if(!rng.size()) return;
if(l + 1 == r || !a.size()){
for(auto [s, t, x, y, id] : rng){
lok[id] = solve(s, t);
}
return;
}
int m = (l + r) / 2;
vector<pll> a1, a2, nax;
for(auto [c, p] : a){
auto [x, y] = road[p];
if(dep[x] < dep[y]) swap(x, y);
if(c > m) a2.eb(c, p);
else{
a1.eb(c, p);
st.upd(in[x], {c, 1});
st.upd(out[x], {-c, -1});
}
if(c == m) nax.eb(c, p);
}
vector<info> r1, r2;
for(auto [s, t, x, y, id] : rng){
auto [cnt, ttl] = solve(s, t);
if(y >= cnt) r2.pb(info(s, t, x, y, id));
else bad[id] = {cnt, ttl}, r1.pb(info(s, t, x, y, id));
}
bs(a2, r2, m, r);
for(auto [c, p] : a1){
auto [x, y] = road[p];
if(dep[x] < dep[y]) swap(x, y);
st.upd(in[x], {-c, -1});
st.upd(out[x], {c, 1});
}
bs(a1, r1, l, m);
}
int ans[maxn];
signed main(void){
fastio;
cin>>n>>m>>q;
for(int i = 0; i < n - 1; i++){
int a, b;
cin>>a>>b;
a--, b--;
adj[a].pb(b);
adj[b].pb(a);
road[i] = {a, b};
}
vector<pll> a(m);
for(int i = 0; i < m; i++){
cin>>a[i].s>>a[i].f;
a[i].s--;
}
sort(a.begin(), a.end());
vector<info> qry;
for(int i = 0; i < q; i++){
int s, t, x, y;
cin>>s>>t>>x>>y;
s--, t--;
qry.pb(info(s, t, x, y, i));
}
dfs(0, -1);
decompose(0, 0);
vector<pll> empt;
bs(a, qry, 0, INF);
for(int i = 0; i < m; i++){
auto [c, p] = a[i];
auto [b, d] = road[p];
if(dep[b] < dep[d]) swap(b, d);
st.upd(in[b], {0, 1});
st.upd(out[b], {0, -1});
}
for(int i = 0; i < q; i++){
auto [s, t, x, y, id] = qry[i];
auto [c1, t1] = lok[i];
auto [c2, t2] = bad[i];
if(t2 <= t1){
ans[i] = x + t1 - solve(s, t).s;
continue;
}
int cnt = (c2 - c1) / (t2 - t1);
int canuse = (y - c1) / cnt;
ans[i] += x + t1 + canuse - solve(s, t).s;
}
for(int i = 0; i < q; i++){
cout<<(ans[i] < 0 ? -1 : ans[i])<<"\n";
}
}
/*
4 5 2
1 2
2 3
3 4
1 5
2 6
3 7
*/
