Nitrogen is a limiting nutrient for both natural and agricultural yield.

The correct option is A True
Nitrogen is the most abundant element in the atmosphere and it forms a major component of several important molecules.

However, the availability of nitrogen in the soil is limited because plants—the primary food producers—lack the ability to fix atmospheric nitrogen. They depend upon nitrogen-fixing soil bacteria to 'fix' (think modify) the nitrogen for them to use unlike carbon or hydrogen which they can modify themselves.

This makes nitrogen a limiting nutrient even though it's the most abundant in the atmosphere. Ironic, isn't it?