$A$: The vaginal orifice is partially covered by a membrane called the hymen.
$R$: It is made up of a thick layer of smooth muscle.

• A
  Assertion and Reason both are correct and Reason is the correct explanation of Assertion.
• B
  Assertion and Reason both are correct but Reason is not the correct explanation of Assertion.
• C
  Assertion is correct,but Reason is incorrect.
• D
  Both Assertion and Reason are incorrect.