JEE Math Practice Question

Let $$f:R \to R$$ be defined as $$f(x) = \left\{ {\begin{matrix} { - 55x,} & {if\,x < - 5} \\ {2{x^3} - 3{x^2} - 120x,} & {if\, - 5 \le x \le 4} \\ {2{x^3} - 3{x^2} - 36x - 336,} & {if\,x > 4,} \\ \end{matrix} } \right.$$ Let A = {x $$ \in $$ R : f is increasing}. Then A is equal to :

1. A.$$( - 5,\infty )$$
2. B.$$( - \infty , - 5) \cup (4,\infty )$$
3. C.$$( - 5, - 4) \cup (4,\infty )$$
4. D.$$( - \infty , - 5) \cup ( - 4,\infty )$$