import math

num_casos = int(input())
for _ in range(num_casos):
    num_bolas = int(input())
    x_b, y_b = [int(x) for x in input().split()]

    menor_distancia = math.inf
    bola_mais_proxima = -1
    for bola in range(1, num_bolas+1):
        x, y = [int(x) for x in input().split()]
        d = math.sqrt(abs(x-x_b)**2 + abs(y-y_b)**2)
        if d < menor_distancia:
            menor_distancia = d
            bola_mais_proxima = bola

    print(bola_mais_proxima)