If V1 is the voltage at port 1 and V2 is the voltage at port 2, then the attenuation in dB is?

• A. 20 log10 (V1/V2)
• B. 10 log10 (V1/V2)
• C. 20 log10 (V2/V1)
• D. 10 log10 (V2/V1)