A client is admitted to the cardiac unit with a diagnosis of pericarditis. The nurse is teaching the patient about the anatomical location of the infection. The nurse evaluates the effectiveness of the teaching when the client correctly identifies which of the following as the location of the pericardium?

a) The innermost lining of the heart chambers
b) A membranous sac that encloses the heart
c) The outer muscular layer of the heart
d) The electrical conduction system of the heart