Correct Answer: Both assertion and reason are true, and the reason is the correct explanation of the assertion.

Solution : The correct answer is (a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.

The assertion that the poverty line in India varies across states is true. In India, the poverty line is not a fixed value but is determined separately for each state. The poverty line is typically calculated based on the cost of living and consumption patterns specific to each state. This approach acknowledges that the cost of living can vary significantly across states due to differences in factors such as food prices, housing costs, transportation expenses, and regional economic disparities.

The reason provided correctly explains why the poverty line varies across states. The cost of living and consumption patterns differ among states in India, leading to variations in the poverty line. By considering these variations, policymakers and researchers can better understand the extent of poverty and design targeted interventions that are appropriate for each state's specific circumstances.

Therefore, both the assertion and reason are true, and the reason is the correct explanation of the assertion.