If this pattern of stock returns is typical of AT&T stock, and you calculated a beta against the S&P 500, which of the following is true?

You observe that AT&T stock and the S&P 500 have the following weekly returns:

Week AT&T return S&P 500 return
1 0.005 0.001
2 0.010 0.005
3 -0.003 -0.005
4 -0.005 -0.001

A) AT&T's beta is negative.
B) AT&T's beta is zero.
C) AT&T's beta is positive.
D) Cannot be determined from information given.

Answer: C