Find (By Hand) All Critical Numbers and Use the First

Multiple Choice

Find (by hand) all critical numbers and use the First Derivative Test to classify each as the location of a local maximum, local minimum or neither. y = x^4/3 - 8x^1/3 - 6

A) x = 0 (neither)
B) x = -2 (local maxima)
C) x = -2 (local minima)
D) x = 2 (local minima) , x = 0 (neither)