The correct answer is: Zone III.
Una, Bilaspur and Hamirpur are all located in the Indian state of Himachal Pradesh. Himachal Pradesh is divided into four zones: Zone I, Zone II, Zone III, and Zone IV. Zone III is the largest zone in Himachal Pradesh, and it includes the districts of Una, Bilaspur, Hamirpur, Kangra, Mandi, and Sirmaur.
Zone I is the smallest zone in Himachal Pradesh, and it includes the districts of Chamba, Kullu, Lahaul and Spiti, and Shimla. Zone II is located in the central part of Himachal Pradesh, and it includes the districts of Solan, Sirmaur, and Shimla. Zone IV is located in the eastern part of Himachal Pradesh, and it includes the districts of Kinnaur, Lahaul and Spiti, and Shimla.
The following is a brief description of each option:
- Option A: Zone I is the smallest zone in Himachal Pradesh, and it includes the districts of Chamba, Kullu, Lahaul and Spiti, and Shimla. Una, Bilaspur and Hamirpur are not located in Zone I.
- Option B: Zone II is located in the central part of Himachal Pradesh, and it includes the districts of Solan, Sirmaur, and Shimla. Una, Bilaspur and Hamirpur are not located in Zone II.
- Option C: Zone III is the largest zone in Himachal Pradesh, and it includes the districts of Una, Bilaspur, Hamirpur, Kangra, Mandi, and Sirmaur. Una, Bilaspur and Hamirpur are all located in Zone III.
- Option D: Zone IV is located in the eastern part of Himachal Pradesh, and it includes the districts of Kinnaur, Lahaul and Spiti, and Shimla. Una, Bilaspur and Hamirpur are not located in Zone IV.