The correct option is
A Anther wall
Tapetum is the innermost layer of anther wall. It is single-layered and the cells have dense cytoplasm and prominent nuclei. A very common feature of the tapetum is that total DNA content increases enormously in the meiotic prophase. It completely surrounds the sporogenous tissue and nourishes the developing pollen grains.
Hence, Tapetum is a part of anther wall. So, the correct answer is A.