Which part of the reproductive structure produces both enzymes and hormones

Identify $A$ to $E$ in the following diagram

Assertion : Pollen mother cells $(PMCs)$ are the first male gametophytic cells.
Reason : Each $PMC$ gives rise to two pollens.

In some members of which of the following pairs of families, pollen grains retain their viability for months after release ?

$A$ : Each cell of the sporogenous tissue is capable of giving rise to a microspore tetrads.
$R$ : Most abundant microspore tetrads is the product of simultaneous cytokinesis.