Answer:
C) The territory´s emblematic stone, blue lazulite, looks bluer than the sky does on a clear summer day.
Explanation:
An adverbial clause is a dependent clause used as an adverb within a sentence to indicate time, place, conditions, reasons, or contrasts.
These types of clauses usually contain a subject and a predicate.
The other options are examples of a who/which clauses while option C indicates contrast.
I hope this answer helps you.
