Correct answer: A. When competition in market is changing
Explanation: The direct answer is A: strategy becomes more important when competition in the market is changing. Strategy is a broad, long-term plan that helps an organisation decide where it wants to go and how it will compete. When competitors change their prices, products, technology, or customer service, an organisation cannot continue blindly with old decisions. It must study the environment, identify opportunities and threats, choose priorities, and use its resources in a suitable way. The reasoning is: changing competition creates uncertainty; uncertainty requires choices; coordinated choices about goals, resources, and competitive action form strategy. Option A is correct because changing market competition may require a new product, lower cost, better delivery, or a different customer group. Option B is wrong because closing a file is a small routine task, not a broad competitive decision. Option C is wrong because cleaning a chair is a physical activity with no strategic direction. Option D is wrong because writing a leave application is an individual administrative action, not a plan for competing in a market. Strategy does not mean performing every small task; it gives direction to major organisational decisions. Memory cue: changing competitors and changing markets call for strategic thinking.