Consider two functions \(f:\mathbb{R}\to\mathbb{R}\) and…

Consider two functions $f:\mathbb{R}\to\mathbb{R}$ and $g:\mathbb{R}\to(1,\infty)$. Both functions are differentiable at a point $c$. Which of the following functions is/are ALWAYS differentiable at $c$? The symbol $\cdot$ denotes product and the symbol $\circ$ denotes composition of functions.