For the following function, find the intervals on which the function is increasing or decreasing.

f(x) = 2x³ - 3x² - 72x + 6

Select the correct:
a) The function is increasing on (-[infinity], -3) and (6, [infinity])
b) The function is increasing on (-[infinity], -[infinity]) and (6, [infinity])
c) The function is decreasing on (-[infinity], -3) and (6, [infinity])
d) The function is decreasing on (-[infinity], -3) and (-3, 6)