Compound annual rate question? equivalent, following, compound

towardsutopia21

Guys, I came across a question today that I could not woek through, i would appreciate clarification, thanks.
An analysis observes the following four annual returns:
R1 = +10%, R2 = 15%, R3 = 0%, R4 = +5%
The equivalent compound annual rate is;
A; 5%
B; 0.5%
C; 0%
D: 7.4%
I came up with answer C 0% where as the correct ana=swer is B; 0.5%
I would be grateful for the workings on this one, many thanks.

Siddimaula

Perdition,
It might be helpful to keep in mind that geometric average factors in the effects of compounding so that is the one you generally want to use when calculating historical returns as that is the best reflection of how your investment actually grew/shrunk.
If the question is in the context of forward looking, or expected return, arithmetic average would be more appropriate.