Which sentence uses an adverb to enrich its meaning?

the elephant lumbered slowly to its water trough.

the wrinkly elephant lumbered to its water trough.

the elephant lumbered to its water trough in the hut.

the elephant lumbered to its leaky water trough.

Which is the most accurate definition of a clause? a) a clause is any group of two or more words. b) a clause is a group of words with a subject and a verb. c) a clause is a group of words with a subject and a verb that can stand alone. d) a clause is a group of words with a subject and a verb that cannot stand alone.