The correct answer is option 3: plant products. This means that a greater population can be supported on Earth if we consume more plant-based foods.

Plant products, such as fruits, vegetables, grains, and legumes, are rich in essential nutrients and can provide us with the energy and nutrients we need for our bodies to function properly. Additionally, plant-based diets tend to have a lower environmental impact compared to diets that include animal products.

Options 1, 2, and 4, which are mutton, eggs, and beef, respectively, are animal-based foods. These foods require more resources, such as water and land, for their production and have a higher carbon footprint compared to plant-based food production. Therefore, consuming more plant products is a sustainable and efficient way to support a larger population on Earth.

Alert - correct answer should be option 3: plant products.