To reflect a function over the x-axis, you have to change the sign of the function, you can express this as:
[tex]g(x)=-f(x)[/tex]We know that the function f(x) has the following formula
[tex]f(x)=3(\frac{1}{2})^x[/tex]Then, after the reflection over the x-axis, the function will have the following shape:
[tex]\begin{gathered} g(x)=-f(x) \\ g(x)=-3(\frac{1}{2})^x \end{gathered}[/tex]The correct option is the second one g(x)=-3(1/2)^x