A small company plans to spend $10,000 in year 2 and $10,000 in year 5. At an interest rate of effective 10% per year compounded semi-annually, the equation that represents the equivalent annual worth in years 1 thru 5 is:

(a) A = 10,000 (A/P, 10%, 4) + 10,000 (A/F, 10%, 5) (b) A = 10,000 (P/F, 5%, 2) (A/P, 5%, 10) + 10,000 (A/F, 5%, 10) (c) A = [10,000(F/P, 10%, 4) + 10,000] (A/F, 10%, 5) (d) A = 10,000 (F/P, 10%, 1) (A/P, 10%, 5) + 10,000 (A/F, 10%, 5)

how is the answer C?