A Bluetooth device can be either a master or a slave and any of the devices within a （71） can be the master．There is only one master and there can be up to （72） active slave devices at a time within a single network．In addition, a device may be a standby slave or a parked slave．There can be up to （73） parked slaves．If there are already maximum number of active slaves, then a parked slave must wait until one of the active slaves switches to （74） mode before it can become active．Within a network, all （75） communications are prohibited.
空白处（75）应选择（）
A．master-to-master
B．master-to-slave
C．slave-to-slave
D．slave-to-master