The answer is A. <span>The poem that I read in class is by Maya Angelou. </span>(The subordinate clause is bolded.)
Subordinate means dependent - so, this clause has elements of a sentence (such as subject and predicate), but it cannot stand on its own. It only adds some information to the main clause. It always has a subordinate conjunction or a relative pronoun (which, whose, whom, etc.) which connects it to the main sentence; in this case, it is a subordinate conjunction that.
Explanation:
7 sacred herbs that are clover, henbane, mistletoe, monkshood, pasque-fiower, primrose and vervain.