help please. I don’t think it is C. 2 because it seems too simple. I also have to explain and show my work. I do not understand

Answer:
[tex]\sqrt[2]{f}[/tex]
Step-by-step explanation:
[tex]\sqrt{2f X 2}[/tex]
Calculate the product
[tex]\sqrt{4f}[/tex]
Simplify the radical
[tex]\sqrt[2]{f}[/tex]