For which interval(s) is the function increasing and decreasing?
y=3x^3-16x=2

A. increasing for −2.31 < x < 2.31; decreasing for x < −2.31 and x > 2.31

B. increasing for x<-4/3 and x>4/3 ; decreasing for -4/3
C. increasing for x<-2.31 and ; x>2.31 ; decreasing for -2.31
D. increasing for-4/34/3