Final answer:
The best instance for this fallacy is Appeal to Ignorance.
Step-by-step explanation:
The best instance for the given fallacy is Appeal to Ignorance.
Appeal to Ignorance occurs when someone argues that a statement is true simply because it hasn't been proven false, or vice versa. In this case, the argument that the paint store is the best place to work on your diet and get thinner is based on the assumption that there is no evidence to suggest otherwise.
Therefore, the correct answer is option 7. Appeal to Ignorance.