You Are a Doctor Examining a Patient's Blood-Test Results

You are a doctor examining a patient's blood-test results. The patient's T cell count is low. You examine scans of the patient's thymus. It is underdeveloped, which means the T cells in the blood will:

A) be present in lower numbers because the thymus is where T cells are formed.
B) be present in lower numbers because the thymus is where T cells mature.
C) not have undergone selection against self-recognition, and the patient will be more susceptible to autoimmune diseases.