How did the seasonal calendar regulate the economy of pastoralists?

Correct answer: It decided when to move towards which pasture and water source

Pastoralists depend on natural pasture and water, and these resources change with the seasons. A seasonal calendar helps them decide when to leave one area, where grass will be available, and when water sources are more dependable. Planning movement in this way protects animals from shortage and helps maintain milk, wool, meat, or other products.

The calendar is therefore a practical guide to movement and resource use, not merely a festival list or a government tax document. By matching grazing routes with seasonal conditions, pastoralists could use different pastures at suitable times and reduce pressure on one place. Hence option C is correct. The other choices do not describe the economic and environmental purpose of seasonal movement.