I would say that the 3rd statement is correct!!
The subject complement is the fallowing a verb which describes the subject.
Answer:
Researchers now believe that dreams help us process emotions, consolidate memories, and more. Sometimes dreams make a lot of sense -- like when we've been working hard and we end up dreaming, alas, that we're still at work. Other times the meaning of dreams is less clear.
Physician assistants (PAs) examine patients, prescribe medicine, and order diagnostic tests. In most cases, they work under the supervision of physicians or surgeons, but they can work more independently in some states, rural areas, and inner-city areas, consulting with physicians only when they need help with cases.