The answer to this question is letter a, true. It is because the person who calls or which we call the caller, has the rights of ending the phone call for he or she is the one who called in the first place. The receiver does not have the responsibility of ending the phone call for he or she is the one who has been called and the only response that he or she must do is reach out or receive the phone call that the caller has reached out to him or her.