Instruction: Analyze the query and product title to determine the relevance between the query and product, and select the appropriate option from the provided options.

Input:
Query: opti filter water
Product: Katadyn BeFree 1.0L Water Filter, Fast Flow, 0.1 Micron EZ Clean Membrane for Endurance Sports, Camping and Backpacking, One Size, 8018006

Options:
A: The product is relevant to the query, and satisfies all the query specifications.
B: The product is somewhat relevant. It fails to fulfill some aspects of the query but the product can be used as a functional substitute.
C: The product does not fulfill the query, but could be used in combination with a product exactly matching the query.
D: The product is irrelevant to the query.
Answer: B: The product is somewhat relevant. It fails to fulfill some aspects of the query but the product can be used as a functional substitute.