Answer:
C. Although rabbits are small, they run faster than grizzly bears.
Explanation:
An adverb clause has the following characteristics:
- It is a dependent clause (a group of words containing a subject and a verb).
- It acts as an adverb, that is to say, to modify or to add more detail to an adjective, a verb or another adverb.
- It is introduced by subordinate conjunctions such as although, after, as, as if, before, because, if, since, so that, unless, until, when, where, and while
- It often gives us information about when, where, why, how, under what conditions, to what extent or in what manner something happened.
The underlined clause "Although rabbits are small" of Option C, then, is the correct option because it has all the characteristics of an adverb clause: It is a dependent clause, it modifies the verb "faster" by giving us information about under what condition rabbits run faster than grizzly bears and it begins with a subordinate conjunction (Although), just like all adverbs do.
