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 have allergies to mold & dust.  My home office is in our basement. This air cleaner keeps
the basement smelling clean and eliminates mold as far as I can tell.  The filter lasts a
long time. It seems expensive when you buy it but in the long run it's worth it for comfort.

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