Cost of Capital Preference Dividend

"Suppose the rate of return on short-term government securities (perceived to be risk-free) is 5%.  Suppose also that the expected rate of return required by the market for a portfolio with a beta of 1 is 12%.  According to the CAPM:
a) What is the expected rate of return on the market portfolio?
b) What would be the expected rate of return on a stock with β = 0?
c) Suppose you consider buying a share of stock at $40. The stock is expected to pay $3 in
dividends next year and you expect to sell it then for $41. The stock risk has been evaluated
at β = −0.5. Is the stock overpriced or underpriced?
"