What is the wireless Received Signal Strength Indicator?

A.	the value given to the strength of the wireless signal received compared to the noise level
B.	the value of how strong the wireless signal is leaving the antenna using transmit power, cable loss, and antenna gain
C.	the value of how much wireless signal is lost over a def ned amount of distance
D.	the value of how strong a wireless signal is received, measured in dBm