The correct answer for the question is option 2, New Delhi.
To understand why this answer is correct, let`s analyze the other options as well.
Option 1: Kolkata - While Kolkata is a major city in India, it was not the host city for the 15th Asia Media Summit.
Option 3: Chennai - Similarly, Chennai is another major city in India, but it was not the host city for the summit either.
Option 4: Bengaluru - Bengaluru, also known as Bangalore, is a prominent city in India, but it was not the host city for the 15th Asia Media Summit.
Therefore, New Delhi is the correct answer because it was indeed the host city for the 15th Asia Media Summit.
In conclusion, the 15th Asia Media Summit was hosted in New Delhi, making option 2 the correct choice.