​A new special attraction opened at a museum. The museum management tracked the number of people who visited the attraction each day and created a function model for the number of people for each day after the attraction opened. Each day they also calculated the rate of change of the number of people visiting the attraction. They created a function model for the rate of change, in people per day, for each day after the attraction opened. The function is given by

. At which of the following values of does the graph of have a point of inflection?