Correct option is D
The north-west agroclimatic zone of Bihar includes
13 districts:
1. East Champaran
2. West Champaran
3. Gopalganj
4. Muzaffarpur
5. Saran
6. Siwan
7. Vaishali
8. Darbhanga
9. Madhubani
10. Samastipur
11. Begusarai
12. Sheohar,
13. Sitamarhi.