The historical returns for two investments A and B are summarized in the following table for the period $2016$ to $2020.$ Use the data that follows.

Year Rate of Return

$201621\mathrm{.}1\%10\mathrm{.}4\%$

$20174\mathrm{.}9\%12\mathrm{.}8\%$

$201812\mathrm{.}2\%14\mathrm{.}6\%$

$201927\mathrm{.}2\%17\mathrm{.}6\%$

a$.$ On the basis of a review of the return$$ data, which investment appears to be more$$ risky? Why?

b$.$ Calculate the standard deviation for each$$ investment's returns.

c$.$ On the basis of your calculations in part b$,$ which investment is more$$ risky? Compare this conclusion to your observation in part a$.$

On the basis of a review of the return$$ data, which investment appears to be more$$ risky? Why?$($Choose the best answer$$ below.$)$

A$.$

The riskier investment appears to be investment$$ B$,$ with returns that are closer to the average relative to investment$$ A$,$ whose returns are farther from the average.

B$.$

The riskier investment appears to be investment$$ A$,$ with returns that vary widely from the average relative to investment$$ B$,$ whose returns show less deviation from the average.

C$.$

The riskier investment appears to be investment$$ B$,$ with returns that vary widely from the average relative to investment$$ A$,$ whose returns show less deviation from the average.

D$.$

Investment A and investment B have equal risk because the average returns are the same

$$The standard deviation for investment A is $......$

The standard deviation for investment B is$....\%($Round to two decimal places$)$