Consider the Following Proposed Determining Function for a Student's Grade

Consider the following proposed determining function for a student's grade on the econometrics final, FinalGrade_i = 68 + 4 HoursStudied_i - 0.5 Num Other Finals_i² + U_i, where hours studied is the number of hours studied during finals week by student i, and number of other finals squared is the number of other finals student i has during finals week squared. Derive the formula for the change in a student's final grade with respect to a unit change in the number of other finals the student has in finals week.

A) Final Grade decreases by 0.5.
B) Final Grade increases by 4.
C) Final Grade increases by 0.5 × (Num Other Finals) .
D) Final Grade decreases by Num Other Finals.