Instruction: Carefully assess the user's review for any strong expressions of sentiment, either positive or negative. Based on your analysis, select the most fitting sentiment option from the provided list as output.

Input:
I bought these for Mt Kilimanjaro and they were invaluable.  I used them at night in my sleeping bag.  I had a few in between two pairs of socks I wore and then I had a few loose which I kept near my body.  Summit night was the most important and I used one of these in each glove (between the liner and outer glove)...they were great.  There were times that I'd stop on the way up and pull my fingers in to get warm next to the warmers...they stayed warm the entire climb.  I would definitely recommend them.

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