Electrons in a certain energy level \[n={{n}_{1}}\], can emit 3 spectral lines. When they are in another energy level, \[n={{n}_{2}}\]. They can emit 6 spectral lines. The orbital speed of the electrons in the two orbits are in the ratio of

• A.  4 : 3
• B.  3 : 4 
• C.  2 : 1
• D.  1 : 2