8. [5 points] Let f (t) describe the temperature (in degrees Fahrenheit) of a cup of coffee t minutes after it has been brewed. a. [2 points] What are the units of f'(t)? b. [3 points] Give an interpretation of the following mathematical expressions in the context of this problem for a non-mathematical friend. i) f(0) = 200 ii) f'(0) = -10 iii) f" (0) > 0