Let \(f:\mathbb{R}\to \mathbb{R}\) be defined as:Let \(A=\{x\in \mathbb{R}:f \text{ is increasing}\}\). Then \(A\) is equal to:
\((-\infty,-5)\cup(-4,\infty)\)
\((-5,-4)\cup(4,\infty)\)
\((-5,\infty)\)
\((-\infty,-5)\cup(4,\infty)\)