Which One of the Following Best Describes an Arithmetic Average

Which one of the following best describes an arithmetic average return?

A) Total return divided by N - 1, where N equals the number of individual returns
B) Average compound return earned per year over a multiyear period
C) Total compound return divided by the number of individual returns
D) Return earned in an average year over a multiyear period
E) Positive square root of the average compound return