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