In the given reaction cycle 
\( X \), \( Y \) and \( Z \) respectively are:
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:
Assertion (A): \( \mathrm{BeCl_2} \) and \( \mathrm{MgCl_2} \) produce characteristic flame
Reason (R): The excitation energy is high in \( \mathrm{BeCl_2} \) and \( \mathrm{MgCl_2} \)
In the light of the above statements, choose the correct answer from the options given below:
