A nurse and a nursing student are performing a physical assessment of a client with pericarditis. The client has an audible pericardial friction rub on auscultation. When leaving the room, the student asks the nurse what causes the sound. The nurse's best response is which of the following? "The layers of the heart become loose from each other and rub together with each heart beat." "The great vessels rub against the pericardium with each heart beat." "The pericardial surfaces lose their lubricating fluid because of inflammation and rub against each other." "The lung surfaces lose their lubrication and rub against the myocardium with each heart beat."