Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ :
Assertion $(A)$ : $BeCl_2$ and $MgCl_2$ produce characteristic flame.
Reason $(R)$ : The excitation energy is high in $BeCl_2$ and $MgCl_2$.
In the light of the above statements,choose the correct answer from the option given below :

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