Determine Which of the Following Is Not True for the Graph

Multiple Choice

Determine which of the following is not true for the graph of $f ( x ) = x ^ { 4 } + 2 x ^ { 3 }$

A) ƒ is continuous on $( - \infty , \infty )$
B) ƒ has a relative maximum at x = 0.
C) ƒ has a relative minimum at $x = - \frac { 3 } { 2 }$
D) ƒ has points of inflection at x = -1,0.
E) ƒ is concave downward on (-1,0) .