Energy levels $A, B$ and $C$ of a certain atom correspond to increasing values of energy, i.e., $E_A < E_B < E_C$. If $\lambda_1, \lambda_2$ and $\lambda_3$ are the wavelengths of radiations corresponding to transitions $C$ to $B, B$ to $A$ and $C$ to $A$ respectively, which of the following relations is correct?

• A
  $\lambda_3 = \lambda_1 + \lambda_2$
• B
  $\lambda_3 = \frac{\lambda_1 \lambda_2}{\lambda_1 + \lambda_2}$
• C
  $\lambda_1 + \lambda_2 + \lambda_3 = 0$
• D
  $\lambda_3^2 = \lambda_1^2 + \lambda_2^2$