Hey there! :D
When you are finding the area of corresponding sides, you square the number of the ratio of the similar lengths.
The screens a little blurry, but I'm assuming the corresponding side is represented as:
[tex] \frac{a}{b} [/tex]
So, you would keep a and b where they are, (you would be confusing the areas if you switched it in any way) and then just square the variables.
[tex] \frac{a^2}{b^2} [/tex]
"C" is the best answer.
I hope this helps!
~kaikers