Explanation:

Let’s look at each option:

- Option 1: Varietal demonstration

- Shows performance of a new crop variety compared to traditional varieties.

- Focus is on types of varieties, not on increasing production per unit area per unit time.

- Option 2: Result demonstration

- Shows actual results from adopting a new practice/technology.

- Demonstrates increased yield or income, but not specifically per unit area per unit time.

- Option 3: Front line demonstration

- Introduced by ICAR (Indian Council of Agricultural Research).

- Specifically designed to show potential production increase “per unit area per unit time” with modern technologies.

- Closely monitored and data-driven, directly conducted by scientists.

- Correct Answer

- Option 4: Method demonstration

- Teaches the process of doing something, e.g., how to use a pesticide sprayer.

- Focus is on methods, not on showing yield increases over time or per area.

- Option 5: None of the above

- Not correct as one option fits the description.

Correct option is:

Option 3: Front line demonstration