In diploid organisms, which of the following undergoes meiosis?

Sporogenous tissue

The correct answer is Option (2) → Sporogenous tissue

The sporogenous tissue refers to a group of compactly arranged homogenous cells located at the center of each microsporangium. These cells are responsible for the formation of microspores through the process of meiosis. Microspores are the precursor cells that eventually develop into pollen grains. Each cell of the sporogenous tissue within the microsporangium has the potential to give rise to a microspore tetrad, which consists of four cells. These cells are referred to as pollen or microspore mother cells (PMCs). The process by which microspores are formed from a PMC through meiosis is known as microsporogenesis. During microsporogenesis, the PMCs undergo meiotic division, resulting in the formation of microspores. These microspores are initially arranged in clusters of four cells, known as microspore tetrads. As the anthers mature and dehydrate, the microspores separate from each other and develop into individual pollen grains. 

Pollen grains represent the male gametophyte in seed plants.The male gamete in angiosperms (flowering plants)  is formed within the pollen grain. This process occurs in the anthers of flowers . When the pollen grain is mature it contains two cells, the vegetative cell and generative cell . The vegetative cell is bigger, has abundant food reserve and a large irregularly shaped nucleus. The generative cell is small and floats in the cytoplasm of the vegetative cell.

There are two synergid cells, which are located on either side of the egg cell in embryo sac. They have elongated filiform apparatus that help in guiding the pollen tube towards the egg cell.