How Many Points of Inflection Are on the Graph of the Function

Multiple Choice

How many points of inflection are on the graph of the function?
$$f ( x ) = 18 x ^ { 3 } + 5 x ^ { 2 } - 12 x - 20$$ Select the correct answer.

A) 5
B) 2
C) 3
D) 4
E) 1