The population of bacteria (in millions) in a certain culture 15 hours after an experimental nutrient is introduced into the culture is given by the function below. 115 Pa): 5 9+52 a) Let y = P(t). Which expression correctly approximates the change in population from 6 to 6.5 hours? 00.5 - P'(6) 00.5 . P'(6.5) OO.5-P'(6) OP'(6.5) OP'(6) 00.5 - P'(6.5) b) Between 6 and 6.5 hours, the population of bacteria approximately changes by million using differentials. Round to 3 decimal places as needed