The correct answer is option 2, Sathanar. Manimekalai is an ancient Tamil epic written by Sathanar. Option 1, Kovalan, is incorrect as Kovalan is a character in the Tamil epic Silappatikaram, not Manimekalai. Option 3, Ilango Adigal, is also incorrect because Ilango Adigal is the believed author of Silappatikaram, not Manimekalai. Option 4, Tirutakkatevar, is incorrect as there is no known author by that name associated with Manimekalai. It is important to note that there are different opinions and debates about the true authorship of Manimekalai, but it is generally accepted that Sathanar is the author.