This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Contraceptives, Subject name: Gynaecology & Obstetrics
A 20 years old nulliparous women is an oral contraceptives pills. She is currently diagnosed as having pulmonary tuberculosis which anti-tuberculous drug decreases the effect of OCP. 
Select and explain. 
A. INH, B. Pyrazinamide, C. Ethambutol, D. Rifampicin
D: Rifampicin
Answer: D: Rifampicin 
Explanation: Rifampicin is known to be an hepatic enzyme inducer hence is not used in conjunction with ocps. Other inducer agents are long term alcohol abuse. rifampicin. anticonvulsants, paicularly phenytoin,carbamazepine,phenobarbitone and primidone. spironolactone. griseofulvin