If f(x)=2x and $g(x)=\Large {\frac{x^2}{2}}\normalsize+1$,then which of the following can be a discontinuous function

Question

$$\begin{array}{1 1}(A)\;f(x)+g(x) & (B)\;f(x)-g(x)\\(C)\;f(x).g(x) & (D)\;\frac{g(x)}{f(x)}\end{array}$$