$A$ - Events after the formation of zygote are called post-fertilization events.
$R$ - In viviparous animals,a young one develops outside the mother's body.

• A
  $A$ and $R$ are correct.
• B
  $A$ and $R$ are incorrect.
• C
  $A$ is correct,$R$ is incorrect.
• D
  $A$ is incorrect,$R$ is correct.