$A$ - Due to meiosis in $MMC$,microspore tetrads are produced.
$R$ - $MMC$ is a large cell containing dense cytoplasm and a prominent nucleus.

• A
  $A$ and $R$ are correct,and $R$ is the correct explanation of $A$.
• B
  $A$ and $R$ are correct,but $R$ is not the correct explanation of $A$.
• C
  $A$ is correct,$R$ is incorrect.
• D
  $A$ is incorrect,$R$ is correct.