The correct answer is: was written.
The Ramayana is an ancient Indian epic poem that was written by Valmiki. It is one of the most important works of Hindu literature and has been translated into many languages. The poem tells the story of Rama, a prince who is exiled from his kingdom and must fight to regain his throne. The Ramayana is a classic tale of good versus evil and has been an inspiration to many people throughout history.
The other options are incorrect because they do not agree with the tense of the sentence. The sentence is in the past tense, so the verb must also be in the past tense. The options “are written” and “will be written” are in the present tense and the future tense, respectively. The option “was been written” is not a grammatically correct sentence.
In conclusion, the correct answer is: was written.