This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
A patient of parkinsonism is managed with L-dopa. If Vit. B-complex is administered concurrently- 
Select and explain. 
A. The action of L-dopa in brain will be potentiated, B. Decarboxylation of L-dopa in brain will be decreased, C. Side effects will be ameliorated, D. Decreased efficacy will result
D: Decreased efficacy will result
Answer: D: Decreased efficacy will result 
Explanation: Ans. is 'd' i.e., Decreased efficacy will result "Pyridoxine abolishes the therapeutic effect of levodopa by enhancing peripheral decarboxylation of levodopa".