Which one of the following statements related to unexpected returns is correct? 1) Unexpected returns generally cause the actual return to vary significantly from the expected return over the long-term. 2) Unexpected returns over time have a negative effect on the total return of a firm. 3) Unexpected returns are relatively predictable in the short-term. 4) All announcements by a firm affect that firm's unexpected returns. 5) Unexpected returns can be either positive or negative in the short term but tend to be zero over the long-term