The correct answer is option 2: 7 percent. Tropical rainforests cover approximately 7 percent of the world`s land area. These rainforests are found near the equator in regions such as South America, Africa, and Southeast Asia. They are characterized by high levels of rainfall and high biodiversity. Option 1 (2 percent) is incorrect because tropical rainforests cover a larger portion of land than 2 percent. Option 3 (10 percent) and option 4 (15 percent) are also incorrect as these percentages overestimate the extent of tropical rainforests. It is important to note that while tropical rainforests cover a relatively small percentage of the world`s land area, they are crucial for maintaining global biodiversity and are often referred to as the "lungs of the Earth" due to their role in oxygen production.