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 who was given primaquine develops dark coloured urine one day after administration of the drug. The likely diagnosis is - 
Select and explain. 
A. Glucose-6-phosphate dehydrogenase deficiency, B. Glucose-6-phosphate deficiency, C. Galactose-6-phosphate dehydrogenase deficiency, D. Galactose-6-phosphataase deficiency
A: Glucose-6-phosphate dehydrogenase deficiency
Answer: A: Glucose-6-phosphate dehydrogenase deficiency 
Explanation: Ans. is 'a' i.e., Glucose-6-phosphate dehydrogenase deficiency o Development of dark coloured urine within one day of administration of primaquine suggests the possibility of intravascular hemolysis and hemoglobinuria. Primaquine can cause hemolysis in patients with G6PD deficiency.