After the nurse administers haloperidol (Haldol) 5 mg P.O. to a client with acute mania, the client refuses to lie down on her bed, runs out on the unit, pushes clients in her vicinity out of the way, and screams threatening remarks to the staff. Which of the following should the nurse do next?

A Follow the client and ask her to calm down. B Tell the client to lie down on the sofa in the community room. C Seclude the client and use restraints if necessary. D Tell the staff to ignore the client's remarks.