Concept:An adjective describing an economy that remains stable and resilient during a crisis is required.Explanation:A is correct because “strong” best matches the idea of withstanding a crisis while staying in a healthy state.“Realistic” refers to being practical or factual, not to economic strength.“Tough” suggests hardship, but does not clearly mean the economy remained stable.“Firm” implies steadiness, yet “strong” is the more natural and powerful word for an economy.Answer:The correct answer is A. strong.