This is a strengthen with a sufficient premise question, so we are looking to find an answer choice that completely fixes the flaw in the argument. The argument proceeds by concluding that one must only buy a pan with a warranty, and supports this statement by saying that manufacturers would not offer warranties if the product was bad.
The flaw here is really not obvious- I would probably not see the flaw until reading the answer choices. A tells us that most people who buy wants would seek reimbursement if the pan was bad.
This actually does point to a flaw in the argument- and fix it. Maybe manufacturers would offer a warranty even if their product was bad- if they thought that very few customers would use that warranty to get their money back. This answer choice contradicts (and indeed fixes) that flaw, so A is correct.