Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ The beam of electrons shows wave nature and exhibits interference and diffraction.
Reason $R:$ Davisson-Germer experimentally verified the wave nature of electrons.
In the light of the above statements,choose the most appropriate answer from the options given below:

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