The correct answer is 'extremely healthy'. Key Points Let's look at the following points- Fit as fiddle means Someone who is as is very healthy and full of energy Thus,the given context concludes that Though Mr Narayan is eighty-eight yet he is in good physical condition Hence, according to the meaning of given Idioms, option 3rd denotes the correct answer. Therefore the correct answer is Additional Information The violin/ fiddle was picked out as the exemplar because of the alliteration of fit and fiddle, and because the violin is a beautifully shaped instrument producing a very particular sound. But then fit came to mean 'in good physical shape and so fit as a fiddle came to mean 'in good condition physically'.