Question

Choose a suitable adverb clause to complete the sentence:
The earthquake was so deadly _____________________.

• A. yet the government did nothing
• B. that hundreds of people died in it
  
• C. and caused so much loss
• D. None of the above

Answer 1

The correct option is B that hundreds of people died in it

An adverb clause is a group of words containing a subject and a verb, and it functions as an adverb, by modifying an adjective, verb or an adverb. Adverb clauses generally begin with a subordinate conjunction (since, because, while, etc.)
Option B is correct because it is an adverb clause of result or consequence, 'so...that' is a pair of conjunctions that refers to result: "that hundreds of people died in it".
Option A is incorrect because it is a coordinate/independent clause, whereas an adverb clause is subordinate/dependent.
Similarly, option C is incorrect because it contains a coordinate clause..
Option D is incorrect because the answer lies in B.