In 1990, the rate of change of the world population was approximately 0.09125 billion per year (or approximately 1 million people every four days). The world population was estimated to be 5.3 billion in 1990. Write an equation to model the population, P (in billions), in terms of t, where t is the number of years since 1990 (t = 0 corresponds to 1990) a. b. c. d. Please select the best answer from the choices provided