Correct Option: A

Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback. Some of the advantages of negative feedback include: gain stability; reduced non-linear distortion, reduced noise, increased bandwidth, increased input impedance and reduced output impedance.