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 bought this for my son who has developed tennis elbow. It has helped to reduce the pain and strengthen his elbow area to where he does feel pain when he hits. One word of advice, after you start using this, don't stop. You need to keep at it daily as in any other therapy.

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