Instruction: Given the user's review, identify the user's sentiment from the listed options. Answer using one of the options.

Input:
This works exactly as advertised. I have a car that I don't drive very often, and I use this to keep the battery charged. When you first plug it in, it works hard to charge up the battery, and it gets warm to the touch. After that it only turns on when needed to top off the battery, and it's very cool to the touch. You can't tell it doesn't use much energy once the battery is charged.

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