A woman who has won a prize is offered a lump sum of $ 600,000.00 to invest now , or $350,000 to invest at the end of this year and another $ 350,000.00 to invest at the end of the following year. If all investments are assumed to earn 20% pa . Which should she choose if she intends to withdraw the money after

a) 6 years

b) 2 years