To solve this problem, we need to determine the purpose of pollen tablets available in the market. Let's analyze each option:$\newline \bullet$Option 1: In vitro fertilization - Pollen tablets are not used for in vitro fertilization. This process typically involves the fertilization of an egg outside the body, often using sperm and eggs, not pollen.$\newline \bullet$Option 2: Breeding programmes - While pollen can be used in plant breeding programs, pollen tablets specifically are not typically used for this purpose.$\newline \bullet$Option 3: Supplementing food - Pollen tablets are indeed used as dietary supplements. They are rich in nutrients and are consumed for their potential health benefits.$\newline \bullet$Option 4: Ex situ conservation - Ex situ conservation involves the preservation of components of biological diversity outside their natural habitats, such as in seed banks or botanical gardens. Pollen tablets are not used for this purpose.$\newline$Based on the analysis, the correct option is Option 3: Supplementing food.