Use a Graphing Calculator to Determine Approximately the Internals on Which

Multiple Choice

Use a graphing calculator to determine approximately the internals on which the function $f$ is decreasing. $f ( x ) = x ^ { 4 } + 6 x ^ { 3 } + x ^ { 2 } - 24 x + 16$

A) $[ - 4 , - 1.5 ] , [ 1 , \infty )$
B) $( - \infty , - 4 ] , [ - 1.5,1 )$
C) $( 0 , \infty )$
D) $( 0 , - 16 )$
E) $( - \infty , - 16 ]$