Given below are two statements $:$ one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A) :$ The outer body of an aircraft is made of metal which protects persons sitting inside from lightning strikes.
Reason $(R) :$ The electric field inside the cavity enclosed by a conductor is zero.
In the light of the above statements,choose the most appropriate answer from the options given below.

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