We have discussed the importance of "beta" and "beta risk" when estimating the Capital Asset Pricing Model (CAPM) or the market model. Betas are very important in finance and are even reported by the mainstream financial press, such as Yahoo! Finance. Which one of the following statements is most accurate when describing the behavior of asset betas across time? (a) Betas can change across time. (b) Betas remain constant across time. (c) Betas become negative during recessionary periods. (d) Betas become negative during periods of economic expansion. (e) Betas can only take positive values.

Directions: This is a multiple choice question.