The correct answer is A. Chaitra.
Nav Samvatsar Utsav is celebrated in the month of Chaitra, which is the first month of the Hindu calendar. It is a time of new beginnings and is celebrated with great pomp and show. People clean their homes, decorate them with flowers and rangolis, and wear new clothes. They also visit temples and offer prayers to the gods.
Chaitra is also the month of the spring equinox, which marks the beginning of the new year in the Hindu calendar. It is a time of great joy and celebration, and people take this opportunity to connect with their loved ones and celebrate the arrival of the new year.
The other options are incorrect because they are not the months of the Hindu calendar. Phalguna is the month before Chaitra, Magha is the month after Chaitra, and Shravana is the sixth month of the Hindu calendar.