Which festival is celebrated in Devi Ahilyabai Fort Complex in the month of…

Many heritage complexes in India host a named, region-specific cultural festival tied to that site or its surrounding region — matching a monument to its festival means identifying which named festival belongs to that place's own region, not to a different region's festival.

The Devi Ahilyabai Fort Complex stands in the Nimar region of Madhya Pradesh, on the banks of the Narmada river. The district administration's official festival calendar records the Nimar Utsav (Nimar festival) as being held at this fort complex every year in December-January, celebrating the folk music, dance, and craft traditions of the Nimar region.

• The Malwa Utsav belongs to the Malwa region of Madhya Pradesh (around Indore and Ujjain), a different region from Nimar.

• The Bhoj Utsav is centred on the temple heritage of Bhojpur, near Bhopal, an entirely different site.

• The Tejaji festival honours the folk deity Tejaji and is mainly observed in Rajasthan and neighbouring areas, unconnected to this fort complex.

Since only the Nimar festival is documented as being held at the Devi Ahilyabai Fort Complex in December-January, it is the correct answer.