What's the main clause in the sentence since the football team was good this year, the homecoming game was sold out

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.