Most Often the Clinician Makes a Diagnosis of Infectious Mononucleosis

Most often the clinician makes a diagnosis of infectious mononucleosis by which of the following findings?

A) significant lymphocytosis, with reactive lymphocytes predominating
B) presence of mild thrombocytopenia, with a significant lymphocytosis
C) demonstration of the presence of the heterophil antibody
D) demonstration of the presence of cytomegalovirus antibody