单选题 A Bluetooth device can be either a master or a slave and any of the devices within a ______can be the master. There is only one master and there can be up to ______ 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 ______.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 ______ mode before it can become active. Within a network, all ______ communications are prohibited.

【正确答案】 D

【答案解析】蓝牙设备可以是一个主设备也可以是一个从设备，位于______中的任一设备都可以成为主设备。在一个网络中只有一个主设备，最多有______个激活的从设备。另外，一个设备可以是活跃的从设备或是休眠的从设备，最多有______个休眠的从设备。如果已有最大数量的活跃从设备，那么，一个休眠的从设备就必须等到某活跃从设备切换到______模式后才能被激活。在一个网络内，所有的______通信都是被禁止的。