Answer:
The answer is c) both a and b.
Step-by-step explanation:
Pollen grains contain the male angiosperm gametophyte that contains two cells:
- Tube cell or tube nucleus which generates a pollen tube from the stigma that grows down into style, enters the ovule microphyte and reaches the embryo sac (female gametophyte). The pollen tube aids the germ cells to reach the ovary.
- Two germ or sperm cells, one of which fuses with the egg, producing the embryo and the other with the central cell, producing the endosperm tissue.