Step 1: Understanding the question.
The question identifies communities or tribes that inhabit the southern slopes and foothills of the Himalayas, particularly across regions of India, Nepal, and Sikkim. The objective is to determine which among the listed groups fit this geographical and ethnic distribution.
Step 2: Analysis of options.
- (A) Dhimal, Thami, Limbu, and Yakha are primarily found in eastern Himalayan regions, particularly in Nepal — partially correct, but not covering all regions mentioned.
- (B) Mewari, Gurung, Murmi, and Sunwari are Himalayan and sub-Himalayan tribes, spread across Nepal and Sikkim; hence, this is correct.
- (C) Khambu, Rai, Vayu, and Aka include groups, but Aka belong to the Arunachal hill tribes, not the Himalayan belt; hence, partially incorrect.
- (D) Sunwari, Kiranti, Lepcha, and Toto correctly represent Himalayan tribes distributed in Sikkim and parts of Northeast India.
Step 3: Conclusion.
Thus, the combinations B and D accurately represent the Himalayan foothill and mountain tribes mentioned in the question.
Step 4: Final Answer.
Hence, the correct answer is (4) B and D Only.