**Core Concept**
The poverty line limit for rural and urban areas in India is defined as the minimum daily calorie intake required to maintain a healthy life, which is determined by the Planning Commission of India. This limit varies between rural and urban areas due to differences in the cost of living and the availability of food.

**Why the Correct Answer is Right**
The poverty line limit for urban areas is set at 2100 calories per person per day. This is lower than the rural poverty line limit of 2400 calories due to the higher cost of living in urban areas. The higher calorie intake in rural areas is necessary to account for the physical demands of manual labor and the lower availability of nutritious food.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a calorie limit for urban areas.
* **Option B:** This option is incorrect because it is the same as the rural poverty line limit, not the urban poverty line limit.
* **Option C:** This option is incorrect because it is higher than the rural poverty line limit and does not accurately reflect the urban poverty line limit.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the poverty line limits are revised periodically to account for changes in the cost of living and the availability of food. The current poverty line limits are based on the Tendulkar Committee recommendations, which were implemented in 2011.

**Correct Answer:** B. 2100