The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
Drawbacks of Rutherford model : This theory could not explain the stability of an atom. According to Maxwell electron loses it's energy continuously in the form of electromagnetic radiations. As a result of this, the e should loss energy at every turn and move closer and closer to the nucleus following a spiral path. The ultimate result will be that it will fall into nucleus, thereby making the atom unstable.
So, Bohr had to postulate that the electrons in stationary orbits around the nucleus do not radiate to give stable atomic model.