The correct answer is D. Dang District.
Dang District is a district in the state of Gujarat, India. It is located in the south-eastern part of the state, and is bordered by the states of Maharashtra and Madhya Pradesh to the south and east, respectively. The district is also bordered by the districts of Valsad to the west, Navsari to the north-west, and Surat to the north.
Dang District is a hilly district, and is home to the Dang Forest, which is one of the largest forests in Gujarat. The district is also home to a number of tribal communities, who make up a significant proportion of the population.
The district headquarters is at Ahwa.
The other options are incorrect because they are all bounded by more than one district.
A. Valsad District is bounded by the districts of Dang, Navsari, Surat, and Maharashtra.
B. Kheda District is bounded by the districts of Anand, Vadodara, Bharuch, Narmada, and Surat.
C. Navsari District is bounded by the districts of Valsad, Dang, Surat, and Maharashtra.