How many pollen tetrads will be formed from $100$ $PMC$s after meiosis?

$A$: Each cell of the sporogenous tissue is capable of giving rise to a microspore tetrad.
$R$: The most abundant type of microspore tetrad is the product of simultaneous cytokinesis.

Ubisch bodies are secreted by

Consider the following statements and choose the correct answer from the given options.
$Statement \ 1$: Innermost layer of microsporangium is tapetum.
$Statement \ 2$: Cells of tapetum possess dense cytoplasm, more than one nucleus, and nourish the developing pollen grains.

Given below are two statements: One is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A) :$ Cells of the tapetum possess dense cytoplasm and generally have more than one nucleus.
Reason $(R):$ Presence of more than one nucleus in the tapetum increases the efficiency of nourishing the developing microspore mother cells.
In light of the above statements,choose the most appropriate answer from the options given below:

If there are $1280$ microspores in a tetralocular anther,how many microspore mother cells will be there in its each pollen chamber?