Which is the following is most correct?

a.	Beta is found by calculating the slope of a plot of historical stock returns vs. historical market returns.

b.	If you were to form a portfolio by randomly selecting stocks, that portfolios beta would be around 0.

c.	The more stocks you add to a portfolio the lower the beta.

d.	It is not possible for a stock to have a negative beta.

e.	All of the answers are correct.