// {{{ by shik
#include <bits/stdc++.h>
#include <unistd.h>
#pragma GCC diagnostic ignored "-Wunused-result"
#pragma GCC diagnostic ignored "-Wunused-function"
#define SZ(x) ((int)(x).size())
#define ALL(x) begin(x), end(x)
#define REP(i, n) for (int i = 0; i < int(n); i++)
#define REP1(i, a, b) for (int i = (a); i <= int(b); i++)
#define MP make_pair
#define PB push_back
using namespace std;
typedef int64_t LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

namespace { namespace shik {

template<class T> void _R(T &x) { cin >> x; }
void _R(int &x) { scanf("%d", &x); }
void _R(int64_t &x) { scanf("%" SCNd64, &x); }
void _R(double &x) { scanf("%lf", &x); }
void _R(char &x) { scanf(" %c", &x); }
void _R(char *x) { scanf("%s", x); }
void R() {}
template<class T, class... U> void R(T &head, U &... tail) { _R(head); R(tail...); }

template<class T> void _W(const T &x) { cout << x; }
void _W(const int &x) { printf("%d", x); }
void _W(const int64_t &x) { printf("%" PRId64, x); }
void _W(const double &x) { printf("%.16f", x); }
void _W(const char &x) { putchar(x); }
void _W(const char *x) { printf("%s", x); }
template<class T> void _W(const vector<T> &x) { for (auto i = x.begin(); i != x.end(); _W(*i++)) if (i != x.cbegin()) putchar(' '); }
void W() {}
template<class T, class... U> void W(const T &head, const U &... tail) { _W(head); putchar(sizeof...(tail) ? ' ' : '\n'); W(tail...); }

#ifdef SHIK
#include "dump.hpp"
#else
#define dump(...)
#endif

template<class T, class F = less<T>> void sort_uniq(vector<T> &v, F f = F()) { sort(begin(v), end(v), f); v.resize(unique(begin(v), end(v)) - begin(v)); }
template<class T> inline T bit(T x, int i) { return (x >> i) & 1; }
template<class T> inline bool chkmax(T &a, const T &b) { return b > a ? a = b, true : false; }
template<class T> inline bool chkmin(T &a, const T &b) { return b < a ? a = b, true : false; }
template<class T> using MaxHeap = priority_queue<T>;
template<class T> using MinHeap = priority_queue<T, vector<T>, greater<T>>;

// }}}

int f( int a, int b ) {
    if ( a>b ) swap(a,b);
    return (a+b)/(a+1);
}

char solve( int a, int b, int x ) {
    x--;
    int l=f(a,b);
    // dump(a,b,x,l);
    if ( a>=b ) {
        int la=0,ra=a;
        while ( la!=ra ) {
            int a1=(la+ra+1)/2;
            int b1=(a1-1)/l;
            int a2=a-a1;
            int b2=b-b1;
            if ( (b2-1)/l>a2 ) {
                ra=a1-1;
            } else {
                la=a1;
            }
        }
        int a1=la;
        int b1=(a1-1)/l;
        int a2=a-a1;
        int b2=b-b1;
        // dump(l,a1,b1,a2,b2);
        if ( x<a1+b1 ) {
            int full=a1/l;
            int ra=a1-full*l;
            assert(ra>=0);
            if ( x<full*(l+1) ) {
                return x%(l+1)==l ? 'B' : 'A';
            } else {
                x-=full*(l+1);
                return x<ra ? 'A' : 'B';
            }
        } else {
            x-=a1+b1;
            int rb=b2-a2*l;
            assert(rb>0);
            if ( x<rb ) {
                return 'B';
            } else {
                x-=rb;
                return x%(l+1)==0 ? 'A' : 'B';
            }
        }
    } else {
        int la=0,ra=a;
        while ( la!=ra ) {
            int a1=(la+ra+1)/2;
            int b1=(a1-1)/l;
            int a2=a-a1;
            int b2=b-b1;
            if ( b1>=b || (b2-1)/l>a2 ) {
                ra=a1-1;
            } else {
                la=a1;
            }
        }
        int a1=la;
        int b1=(a1-1)/l;
        int a2=a-a1;
        int b2=b-b1;
        // dump(l,a1,b1,a2,b2);
        if ( x<a1+b1 ) {
            int full=a1/l;
            int ra=a1-full*l;
            assert(ra>=0);
            if ( x<full*(l+1) ) {
                return x%(l+1)==l ? 'B' : 'A';
            } else {
                x-=full*(l+1);
                return x<ra ? 'A' : 'B';
            }
        } else {
            x-=a1+b1;
            int rb=b2-a2*l;
            assert(rb>0);
            if ( x<rb ) {
                return 'B';
            } else {
                x-=rb;
                return x%(l+1)==0 ? 'A' : 'B';
            }
        }
    }
}

void main() {
    int t;
    R(t);
    while ( t-- ) {
        int a,b,l,r;
        R(a,b,l,r);
        dump(a,b,l,r);
        char ans[1024];
        REP1(i,l,r) {
            char c=solve(a,b,i);
            ans[i-l]=c;
        }
        ans[r-l+1]=0;
        W(ans);
    }
}

// {{{ main
}}
int main() { shik::main(); return 0; }
// }}}


Measured memory_bytes: 384