You need to accumulate $ 21,000 to fund a round-the-world trip in 4 years' time. To do this, you will make 8 equal deposits (half yearly) with the first deposit today. If you earn 7.8% per annum compounding twice yearly, what regular deposit will be needed? (round to nearest cent; don't use $ sign or commas) Select one: O a. $4674.13 O b. $4335.93 O c. $2287.22 O d. $2201.36