You have the following rates of return for a risky portfolio for several recent years:

2016 23.23%

2017 18.76%

2018 8.75%

2019 21.35%

The annualized (geometric) average return on this investment is ________.

a.15.60%

b.13.15%

c.12.83%

d.13.87%

Getting really off numbers.