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 the photons corresponding to the transitions shown in the figure,then:

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