Drug therapy of tuberculosis differs from that of most other infections because:

A. Patients usually require therapy for a shorter period: This is incorrect. TB therapy typically lasts for several months, longer than most other bacterial infections. B. Patients with tuberculosis have no symptoms: This is incorrect. Many patients with active TB do exhibit symptoms such as cough, fever, night sweats, and weight loss. C. Mycobacteria have a cell wall that is resistant to penetration by anti-infective drugs: This is correct. The mycobacterial cell wall is complex and impermeable, requiring specialized drugs and prolonged treatment. D. Anti-tuberculosis drugs are used extensively for treating active disease, not preventing it: This is partially true, but TB drugs are also used for latent TB infection to prevent it from becoming active. Thus, it is not a primary reason differentiating TB therapy from other infections.