Answer: The correct option is A.
Explanation:
The given function is,
[tex]f(x)=\frac{2}{5}(10)^x[/tex]
If a function is reflect across the x-axis, then the x-coordinate remains the same but the sign of y coordinate change.
[tex](x,y)\rightarrow(x,-y)[/tex]
[tex]g(x)=-f(x)[/tex]
[tex]g(x)=-\frac{2}{5}(10)^x[/tex]
The graph of f(x) and g(x) in shown in below figure.
Therefore option A is correct.
