Orange coloured urine is due to:
The urine and the secretions of the patients receiving Rifampicin becomes orange-red and it is harmless. Such a side effect is not encountered with the other three anti-tubercular drugs mentioned as choices. Ref: K D Tripathi Textbook of Pharmacology, 5th Edition, Pages 698-701
Rifampicin
INH
Pyrazinamide
Ethambutol