Step 1: Break the name.
Bharat Rang Mahotsav means the festival of Indian theatre. The national level theatre body of India is the National School of Drama.
Step 2: Recall history.
NSD began this festival in 1999 as part of its 50 year activities and has held it every year since, in Delhi and in other cities.
Step 3: Judge the other options.
The other three are university departments and schools. Such bodies send their productions to the festival as participants, but only NSD is the organiser.
Final Answer:
The answer is option (1), National School of Drama.