Blood analysis reveals lymphocytosis and his sputum is positive for acid-fast bacilli

A 26 year old man complains of cough, night fever, loss of weight, anorexia and night sweats for six weeks presents to his physician. Physical examination reveals vital signs within normal limits except for slight fever. Chest x-ray shows a small cavity in the right middle lobe and enlarged bronchopulmonary lymph nodes. Blood analysis reveals lymphocytosis and his sputum is positive for acid-fast bacilli.
A treatment plan is discussed with the patient and he starts taking his medications.
Which of these drugs acts by inhibition of formation of mycolic acid?
A-Ethambutol
B-Isoniazid
C-Pyrazinamide
D-Rifampin
E-Streptomycin
Answer: https://goo.gl/3Qs9Hm

Ans B