Explanation : Go-back-N has better line utilization is incorrect statement. Because if there is an error at the receiver the frames must be retransmitted where the error occurred in the transmission.
Option (A) statement is correct because in Go- Back-N method sometimes when acknowledgement is not received by sender then sender assumes that packet is not received by receiver so he again sends the packet. So receiver requires more memory to store. and option (C) statement is incorrect because if there is an error at the receiver, the frames must be retransmitted where the error occurred in the transmission. So, answer is 'C'.