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 needed to find a way to keep bats from roosting in the ceiling beams of a vintage observatory I manage -- the beams and the inside of the dome were favored by the local bat population. I did not want to kill or injure the beneficial critters, just keep them outdoors. After some research I discovered this device. The racket it makes is unpleasant to the human ear and, while I find it makes me nervous and uncomfortable when running, I suspect it is all the more disruptive to bat-ears. Once I started running the repeller the bats cleared out, even though we have been unable to close the openings to the dome. The rare bat will brave the noise in the winter time to fall into hibernation -- fortunately they don't poop when stuporous -- but bats are no longer a problem for us thanks to this device.

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