In order to avoid waste of resources caused by the failure of the occupied channel to be released in time after the quality of the wireless interface deteriorates, the GSN protocol uses a timer for wireless link monitoring on the base station side. Which of the following is the timer?

In order to avoid waste of resources caused by the failure of the occupied channel to be released in time after the quality of the wireless interface deteriorates, the GSN protocol uses a timer for wireless link monitoring on the base station side. Which of the following is the timer?
A . Radio link failure counter
B. Downlink failure counters
C. Number of SACCH multiframes
D. Wireless link connection timer

Answer: C