#include <iostream>
#include <string>
#include <cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<iomanip>
#define _USE_MATH_DEFINES
#include <math.h>
#include <functional>
#include<complex>
using namespace std;

#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)

typedef long long ll;
const ll INF = 1e17;
const ll MOD = 1000000007;
const ll MAX = 4000001;
const long double eps = 1E-14;

ll max(ll a, ll b) {
	if (a > b) { return a; }
	return b;
}

ll min(ll a, ll b) {
	if (a > b) { return b; }
	return a;
}

ll gcd(ll a, ll b) {
	if (b == 0) { return a; }
	if (a < b) { return gcd(b, a); }
	return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

struct edge {
	ll ind;
	ll fr;
	ll to;
	ll d;
};

class mint {
	long long x;
public:
	mint(long long x = 0) : x((x% MOD + MOD) % MOD) {}
	mint operator-() const {
		return mint(-x);
	}
	mint& operator+=(const mint& a) {
		if ((x += a.x) >= MOD) x -= MOD;
		return *this;
	}
	mint& operator-=(const mint& a) {
		if ((x += MOD - a.x) >= MOD) x -= MOD;
		return *this;
	}
	mint& operator*=(const  mint& a) {
		(x *= a.x) %= MOD;
		return *this;
	}
	mint operator+(const mint& a) const {
		mint res(*this);
		return res += a;
	}
	mint operator-(const mint& a) const {
		mint res(*this);
		return res -= a;
	}
	mint operator*(const mint& a) const {
		mint res(*this);
		return res *= a;
	}

	mint pow(ll t) const {
		if (!t) return 1;
		mint a = pow(t >> 1);
		a *= a;
		if (t & 1) a *= *this;
		return a;
	}

	// for prime MOD
	mint inv() const {
		return pow(MOD - 2);
	}
	mint& operator/=(const mint& a) {
		return (*this) *= a.inv();
	}
	mint operator/(const mint& a) const {
		mint res(*this);
		return res /= a;
	}

	friend ostream& operator<<(ostream& os, const mint& m) {
		os << m.x;
		return os;
	}
};

mint pw(mint a, ll b) {
	if (b == 0) { return 1; }
	mint ret = pw(a, b >> 1);
	ret *= ret;
	if (b & 1) { ret *= a; }
	return ret;
}

typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<vector<vector<ll>>> vvvll;

typedef vector<mint> vmint;
typedef vector<vector<mint>> vvmint;
typedef vector<vector<vector<mint>>> vvvmint;

//////////////////////////////////////
vector<bool> solve(ll A, ll B, ll C, ll D) {
	ll k = max((A - 1) / (B + 1) + 1, (B - 1) / (A + 1) + 1);

	ll fst = 0;
	if (k == 1) {
		if (A > B) { fst = B; }
		else { fst = 0; }
	}
	else { fst = (k * (A + 1) - B-1) / (k * k - 1); }

	A -= k * fst;
	B -= fst;

	ll snd = (k * (A + 1) - B) / k;
	A -= snd;
	ll th = B - k * A;

	vector<bool> ret;
	for (ll i = C; i <= D; i++) {
		if(i<=fst*(k+1)){
			if (i % (k + 1) == 0) { ret.push_back(1); }
			else { ret.push_back(0); }
		}
		else if (i <= fst * (k + 1) + snd) { ret.push_back(0); }
		else if (i <= fst * (k + 1) + snd + th) { ret.push_back(1); }
		else {
			ll j = i - fst * (k + 1) - snd - th;
			if (j % (k + 1) != 1) { ret.push_back(1); }
			else { ret.push_back(0); }
		}
	}

	return ret;
	
}

int main() {
	ll Q;
	cin >> Q;
	repn(q, Q) {
		ll A, B, C, D;
		cin >> A >> B >> C >> D;

		vector<bool> ans = solve(A, B, C, D);

		for (ll x : ans) {
			if (x) { cout << 'B'; }
			else { cout << 'A'; }
		}
		cout << endl;
	}

}

Measured memory_bytes: 3600