Since 6 months is equal to 0.5 years, evaluate the function at x=0.5 to find the value of the investment after 6 months:
[tex]\begin{gathered} f\mleft(x\mright)=6000\left(1.04\right)^x \\ \\ \Rightarrow f\mleft(0.5\mright)=6000\left(1.04\right)^{0.5}=6118.82...\approx6119 \end{gathered}[/tex]Therefore, the value of the investment after 6 months is approximately $6119. The correct choice is option A) $6,119.