This question checks how well you know the body of work of Mira Nair, the Indian-American director known for stories rooted in Indian social life told with a documentary-like realism.
Three of the four titles, Monsoon Wedding, Kamasutra, and Salaam Bombay, are Mira Nair films. Earth stands apart because Deepa Mehta made it, not Mira Nair.
Let's summarize:
So the film not directed by Mira Nair is Earth, making option (A) the correct answer.