Energy levels A, B, C of a certain atom corresponding to increasing values of energy i.e. $E_A<E_B<E_C$. If ${\lambda }_1,{\lambda }_2,{\lambda }_3$ the wavelengths of radiations corresponding to the
transitions C to B, B to A and C to A, respectively, which of the following statements 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

  ${\lambda }_3^2={\lambda }_1^2+{\lambda }_2^2$