AFRI$-$BANK wants to advertise an investment opportunity to its current and potential clients. The particulars of this investment will be that the client must invest at least R$10000.$ The effective interest rate will be $9,20\%$ per annum and interest will be earned on a six$-$monthly basis. They want to know what the nominal interest rate of this investment opportunity will be$.$ Set your calculator to four decimal places for calculations and round the final answer to two decimal places. Slight rounding differences may occur $-$ choose the alternative that is closest to your answer.

$($a$)38,49\%$

$($b$)18,40\%$

$($c$)11,06\%$

$($d$)9,00\%$

Select one:

a$.$

$38,49\%$

b$.$

$9,00\%$

c$.$

$11,06\%$

d$.$

$18,40\%$