According to Hindu calendar, Diwali falls in which of the following months?

The correct option is Kartika.

Explanation:
Diwali, also known as Deepavali, is the festival of lights. According to the Hindu lunisolar calendar, Diwali is celebrated on the 15th day of the dark fortnight (Amavasya or new moon night) in the month of Kartika (which corresponds to mid-October to mid-November in the Gregorian calendar).

Overview of the Hindu months listed in the choices:
• Magha: Associated with festivals such as Vasant Panchami and Magha Mela.
• Ashwin: Precedes Kartika; major festivals like Sharad Navratri and Vijayadashami (Dussehra) take place during this month.
• Chaitra: The first month of the Hindu calendar, marking the Hindu New Year (Gudi Padwa / Ugadi) and Rama Navami.
• Kartika: The month in which major light festivals such as Diwali and Dev Deepawali are celebrated.

Therefore, according to the Hindu calendar, Diwali falls in the month of Kartika.