Correct Answer: Antartic

Solution : The incorrectly spelt word is marked by the fourth option.

Explanation: The correct spelling of the word referring to the southern polar region is "Antarctic", not "Antartic". The given spelling is missing the letter "c" after the letter "r". The incorrect spelling in the fourth option deviates from the standard English spelling rules for this geographical term.

Therefore, the correct spelling of the word is Antarctic .