Given below are two statements: One is labelled as Assertion $A$ and the other labelled as Reason $R$.
Assertion $A:$ Antihistamines do not affect the secretion of acid in stomach.
Reason $R :$ Antiallergic and antacid drugs work on different receptors.
In the light of the above statements,choose the correct answer from the options given below:

• A
  $A$ is false but $R$ is true
• B
  Both $A$ and $R$ are true and $R$ is the correct explanation of $A$
• C
  $A$ is true but $R$ is false
• D
  Both $A$ and $R$ are true but $R$ is not the correct explanation of $A$.