Determine the Open Intervals on Which the Graph Of $f ( x ) = 2 x ^ { 2 } + 5 x - 4$

Multiple Choice

Determine the open intervals on which the graph of $f ( x ) = 2 x ^ { 2 } + 5 x - 4$ is concave downward or concave upward.

A) concave upward on $( - \infty , 0 )$ ; concave downward on $( 0 , \infty )$
B) concave downward on $( - \infty , \infty )$
C) concave upward on $( - \infty , \infty )$
D) concave downward on $( - \infty , 0 )$ ; concave upward on $( 0 , \infty )$
E) concave upward on $( - \infty , 1 )$ ; concave downward on $( 1 , \infty )$