As an experienced technician, you are responsible for Technical Support. A customer calls to ask the best signal level and noise level for cell phone. How to respond?

A.
-40dBm signal and -90dBm noise

B.
-50dBm signal and -90dBm noise

C.
-30dBm signal and -90dBm noise

D.
-20dBm signal and -90dBm noise

Explanation: