Option 1 states that INS Mambas sailed off to the coast of the United Kingdom because it is a battleship on loan from the UK, and it was returned to them after the loan period was over. However, this option is incorrect because there is no mention of INS Mambas being on loan from the UK in the question.
Option 2 states that India and the UK held a joint naval exercise, and INS Mambas sailed off to the coast of the United Kingdom as part of this exercise. This option is correct because it aligns with the information given in the question. It suggests that INS Mambas` presence off the coast of the United Kingdom was a result of a joint naval exercise between India and the UK.
Option 3 states that INS Mambas sailed off to the coast of the United Kingdom to participate in the celebrations of the anniversary of the Battle of Trafalgar. There is no mention of such celebrations in the question, making this option incorrect.
Option 4 states that INS Mambas sailed off to the coast of the United Kingdom as part of the ship`s circumnavigation of the globe. Again, there is no mention of the ship`s circumnavigation in the question, making this option incorrect.
In conclusion, option