Option 1 is incorrect because although both the assertion and reason are true, the reason does not explain why Saluva Narasimha assumed the royal title.

Option 2 is incorrect because while both the assertion and reason are true events, the reason does not fully explain why Saluva Narasimha put an end to the old dynasty and assumed the royal title. His motivation may not have been solely to "save the kingdom from further degeneration and disintegration."

Option 3 is correct as Saluva Narasimha certainly did put an end to the old dynasty and assumed the royal title. This much is factual. However, the reasoning that he did this specifically to save the kingdom from further degeneration and disintegration is not substantiated. Whilst it could be a part of his motivations, it is not the complete explanation.

Option 4 is incorrect because the assertion is, in fact, true. Additionally, the reasoning given also holds some validity, but it`s not a complete or indeed the only reasoning for the assertion.