Answer:
Many Sherpas are highly regarded as elite mountaineers and experts in their local area. They were valuable to early explorers of the Himalayan region, serving as guides at the extreme altitudes of the peaks and passes in the region, particularly for expeditions to climb Mount Everest.
The group of words that qualifies as a dependent clause as written on the options, is letter A. Because there is no evidence. The rest of the sentences are independent clauses. The word 'because' is a kind of conjunction that begins with a dependent clause. Therefore, the answer is letter A.
Assure could mean making sure something happens, to comfort or remove doubts from a person, or make someone sure of something.
If it's one word answers it could be persuading, guaranteeing, promising, convincing, reassure, satisfy, or tell.
I hope this helps without answer choices it's kind of hard to know what kind of answer you need. Have a great day!