Number of Nuclei present in a pollen grain are

The correct option is D 3
Each pollen grain contains two cells a vegetative cell and generative cell or germ cell. The generative cell has two nuclei- tube nucleus and a generative nucleus. This generative nucleus divides and gives rises to two sperm nuclei, therefore, there are total three nuclei-one tube nucleus and two sperm nuclei.

So the correct answer is "3".