A 2-Year-Old Girl Has Had Repeated Ear and Upper Respiratory

A 2-year-old girl has had repeated ear and upper respiratory infections since she was born. A pediatrician has determined a diagnosis of transient hypogammaglobulinemia of infancy. What is the physiological origin of the child's recurrent infections?

A) The child's immune system is unable to synthesize adequate immunoglobulin on its own.
B) The child had a congenital absence of IgG antibodies that her body is only slowly beginning to produce independently.
C) The child was born with IgA and IgM antibodies, suggesting intrauterine infection.
D) The child lacks the antigen-presenting cells integral to normal B-cell antibody production.