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 has subclinical folate deficiency. Which of the following drug cannot precipitate megaloblastic anemia in this patient? 
Select and explain. 
A. Alcohol, B. Metformin, C. Proguanil, D. Chloroquine
D: Chloroquine
Answer: D: Chloroquine 
Explanation: Megaloblastic anaemia can be caused by a deficiency of folic acid or vitamin B12. The drugs that can result in a deficiency of folic acid include:
B – B12 and folic acid deficiency
A – Alcohol
T – Trimethoprim
S – Sulfasalazine
M – Metformin
A – Antifolates (Methotrexate, pyrimethamine, proguanil)
N – N2O