On a island, the population of flamingos is currently 400, and this population doubles every 3 years. Which of the following functions will correctly model this situation? Assume t is measured in years.
 F f(t)= 2 x 400^3t
 G f(t)= 400 x 3^t/2
 H f(t)= 400 x 2^t/3
 J f(t)= 400 x 2^3t