#include <bits/stdc++.h>
#include <atcoder/all>

using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)
#define all(x) begin(x), end(x)
template <class T> bool chmin(T& x, T y) {
	return x > y ? (x = y, true) : false;
}
template <class T> bool chmax(T& x, T y) {
	return x < y ? (x = y, true) : false;
}

using mint = atcoder::modint998244353;

void solve() {
	ll a, b, k;
	cin >> a >> b >> k;
	if (b == 1 || b == 0 || k == 1 || a == 0) {
		cout << max(0LL, a * k) << '\n';
		return;
	}
	if (b == -1) {
		cout << max({0LL, a * k, -a * (k - 1)}) << '\n';
		return;
	}
	if (k == 2) {
		cout << max({0LL, a, a * 2, a * b}) << '\n';
		return;
	}
	if (a * b > 0) {
		if (a < 0 && k % 2 == 1)
			cout << (mint(b).pow(k - 2) * (2 * a)).val() << '\n';
		else cout << (mint(b).pow(k - 1) * a).val() << '\n';
	} else {
		if (a < 0) cout << "0\n";
		else {
			if (k % 2 == 1) cout << (mint(b).pow(k - 1) * a).val() << '\n';
			else cout << (mint(b).pow(k - 2) * (2 * a)).val() << '\n';
		}
	}
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(15);
	int t = 1;
	cin >> t;
	while (t--) solve();
}