The returns of the S&P 500 (primary US stock market index) for 2020, 2021 and 2022 (to date) are listed below. Treat the partial year 2022 return provided as though it is a full year return (in other words, don't worry about the fact that we are only part of the way through 2022, treat this return like any other annual return when calculating returns). S&P 500 Returns 2020: 16.26% 2021: 26.89% 2022: -17.96% What is the arithmetic average return of the S&P 500 over the 2020 to 2022 period? O (a) 5.60% O (b) 6.57% O (c) 8.40% O (d) 16.26% O (e) 21.03%