Ineed figuring out the difference between who and whom and i dont understand the he or him trick

M read the sentence. what best describes the underlined part of the sentence, and why? alma plans to visit london and paris, where her parentswent on their first trip together as a married couple. it is a restrictive relative clause because it begins with arelative pronoun, has both a subject and a verb, and is notnecessary to the meaning of the sentence. it is a nonrestrictive relative clause because it begins witha relative pronoun, has both a subject and a verb, and isnecessary to the meaning of the sentence. it is a restrictive relative clause because it begins with arelative pronoun, has both a subject and a verb, and isnecessary to the meaning of the sentence. it is a nonrestrictive relative clause because it begins witha relative pronoun, has both a subject and a verb, and isnot necessary to the meaning of the sentence.