Instruction: Determine the sentiment expressed by the user in her review from the provided choices, and respond by selecting one of the available options.

Input:
I don't know the function of this UV protection filter because I did not realize the function this product when I was using this. I got this for free with a deal.

Options:
A: very positive
B: positive
C: neutral
D: negative
E: very negative
Answer: A: very positive