Final answer:
The method used to find absolute maxima and minima on open intervals is by analyzing critical points, not by evaluating the endpoints or applying the Mean Value Theorem.
Step-by-step explanation:
When finding the absolute maximum and minimum on open intervals for a function f(x), the primarily used method is analyzing critical points within the interval. Since the question does not mention closed intervals, evaluating the function at the endpoints is not applicable here (b is incorrect). The Mean Value Theorem (d) is not directly used to find the absolute extrema; rather, it provides a relationship between the function's average rate of change over an interval and the instantaneous rate of change at a point in that interval. To find critical points, one would typically take the derivative of the function and solve for where the derivative is equal to zero or undefined. These points are where the function's rate of change is zero, which indicates possible local maxima or minima. However, for an open interval, we cannot guarantee these will be absolute unless we analyze the behavior of the function near the endpoints of the interval, utilizing limits if necessary.