What should be checked first to make a business idea successful?

Correct answer: What problem the idea will solve

A business idea should begin with a real customer or social problem and a plausible solution. Checking this first helps determine whether there is a genuine need, who experiences it, and whether customers may value the proposed answer. A name, wall colour, or owner’s age may matter in limited circumstances, but none validates the core business opportunity. Thus, A is correct.