$\text { Determine the open intervals on which the graph of } f ( x ) = 3 x ^ { 2 } + 7 x - 3 \text { is concave }$

Multiple Choice

$\text { Determine the open intervals on which the graph of } f ( x ) = 3 x ^ { 2 } + 7 x - 3 \text { is concave }$ downward or concave upward.

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