Correct answer is (b) 1
Easy explanation: Similar to the transistor emitter follower, the source follower configuration itself provides a high level of buffering and a high input impedance. The actual input resistance of the FET itself is very high as it is a field effect device. This means that the source follower circuit is able to provide excellent performance as a buffer. The voltage gain is unity, although current gain is high. The input and output signals are in phase.