During a routine checkup, a nurse observes that a 4-year-old child has noticeably enlarged tonsils but is otherwise healthy with no signs of infection. The child's parents express concern. Which statement BEST explains this finding?

A. Tonsils are part of the lymphatic system, which is most active in early childhood to help the body respond to infections and build immunity. It is common for tonsils to appear large in healthy children between ages 3 and 6. This is a normal physiological finding and usually does not indicate illness unless accompanied by symptoms such as fever, difficulty breathing, or recurrent infections. B. While significantly enlarged tonsils causing airway obstruction, sleep apnea, or recurrent infections may require evaluation, tonsillar enlargement alone in an otherwise healthy child is typically normal and does not require urgent referral. C. Enlarged tonsils in this age group indicate a normally active immune system, not underdevelopment. They help the body recognize and respond to antigens, supporting healthy immune function. D. Chronic or acute infections may cause tonsillar enlargement, but in the absence of symptoms such as fever, redness, or exudate, there is no evidence of infection, and antibiotics are not indicated.