What would you expect the effect to be of the following changes on the market price of a company's shares, all other things being the same? Provide an explanation of your expectation.
a. Investors demand a higher required rate of return on shares in general
b. The covariance between the company's rate of return and that for the market decreases
c. The standard deviation of the probability distribution of rates of return for the company's stock increases
d. Market expectations of the growth of future earnings (and dividends) of the company are revised downwards.