The rate at which people are becoming infected (in person per day) during the outbreak of a disease was approximated by the function mentioned below, where x is in days and x = 0 corresponds to the start of the outbreak. Complete parts (a) and (b) below. f(x) = 4xe (a) Find the function F(x) that gives total number of people who have become infected by day x given that 12 people were infected when x = 0. Select the correct choice below and fill in the answer box to complete your choice. O A. To find F(x), evaluate the antiderivative of f(x). Therefore F(x) = (Type an exact answer.) B. To find F(x), evaluate the derivative of f(x). Therefore F(x) = (Type an exact answer. )