The given passage is about a dog who was trapped in a ship from Calcutta and circumstances led it to reach home safely. From these options, 'reached' is the most suitable option, as it means 'to arrive at', and the ship arrives at Calcutta. Unlike the other options, it does not require a preposition, hence option A is correct. A preposition is a word that links a noun to another word or sentence, and 'reached' does not require one. The other options 'returned' and 'arrived' mean the same thing, 'returned' means coming back to a former place or state, here the dog 'returned' back to Calcutta. 'Arrived' means 'to reach one's destination', the dog reached his destination, Calcutta. But, they both require a preposition to link it with the noun (Calcutta), 'returned to' and 'arrived in/at', we don't have these prepositions given. Hence options B and C are incorrect. 'Advanced' means 'to move or bring forward'. To be placed in the sentence, it would require a preposition, 'advanced towards Calcutta', and we don't have a preposition in this option, hence D is incorrect.