Which of These Are Advantages of Using Panel Data

Multiple Choice

Which of these are advantages of using panel data?
(I) We can address a broader range of issues and tackle more complex problems than would be possible with pure time-series or pure cross-sectional data alone
(II) It allows us to increase the number of degrees of freedom
(III) It allows us to increase the power of the tests
(IV) We can remove the impact of certain forms of omitted variables bias in regression results

A) I only
B) I and II only
C) I, II and III only
D) I, II, III and IV