We have the following:
[tex]\begin{gathered} f\mleft(x\mright)=|x| \\ R=y\ge0 \\ \text{ now,} \\ a<0 \\ g(x)=a|x| \end{gathered}[/tex]Being a less than 0, all the values that are multiplied were less than zero or zero, because even if a does not include 0, x can be 0, therefore, the range would be:
[tex]y\leq0[/tex]The answer is the option D