有7名运动员参加象棋比赛，如果每两人之间都要赛一场，一共要比赛请选择ABC3G3Q,S;{7P(])Q-m4n7{2e8s1s6b'Y'H:F4k-S2q4y,j4_9D;J.M6]
A．14场'Y'H:F4k-S2q4y,j4_9D;J.M6]
B．21场'Y'H:F4k-S2q4y,j4_9D;J.M6]
C．28场'Y'H:F4k-S2q4y,j4_9D;J.M6]