Final answer:
Ten ear infections in the past year would alert the nurse to suspect a primary immunodeficiency.
Step-by-step explanation:
One of the options in the question that would alert the nurse to suspect a primary immunodeficiency is (c) Ten ear infections in the past year. Recurrent and overwhelming infections, especially in infants, can be a sign of primary immunodeficiency. Primary immunodeficiency is caused by inherited defects of either nonspecific innate or specific adaptive immune defenses. Patients with primary immunodeficiency commonly have an increased susceptibility to infection.