The correct answer is option 3: Taungya system. The Taungya system is a traditional agroforestry practice where agricultural crops are grown in the spaces between rows of planted trees. This system is commonly used in tropical regions and has been practiced for centuries. It is a sustainable approach that allows farmers to make efficient use of land by combining the benefits of both tree cultivation and crop production. The trees provide shade, help to prevent soil erosion, and act as windbreaks, while the crops provide food and income for the farmers. This system is especially beneficial for small-scale farmers as it maximizes the use of available land and resources.