The santa catalina mountains-you should be able to notice the verb loom. even if you don�t quite understand it, it should be noticeable that it is the verb. additionally, by skimming the possible answers, one can identify they do not have a verb. having identified the verb, we can clearly understand we need a subject for this sentence.
it is not letter d since the first word is that. it is not letter c since it has the linking verb are, and the verb in the sentences has no -ing ending. it is not letter b since it starts with because. the correct answer is a.