A 1 mW video signal having a bandwidth of 100 MHz is transmitted to a receiver through a cable that has 40 dB loss. If the effective one-sided noise spectral density at the receiver is $$10^{-20}$$ Watt/Hz, then the signal-to-noise ratio at the receiver is

A

50 dB

B

30 dB

C

40 dB

D

60 dB