Find the Largest Open Intervals Where the Function Is Concave $f(x)=x^{3}-3 x^{2}-4 x+5$

Multiple Choice

Find the largest open intervals where the function is concave upward.
- $f(x) =x^{3}-3 x^{2}-4 x+5$

A) $(-\infty, 1) ,(1, \infty)$
B) $(1, \infty)$
C) $(-\infty, 1)$
D) None