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: Social & Preventive Medicine
Which one of the following is NOT an absolute contraindication for oral contraceptive pills? 
Select and explain. 
A. Cancer of breasts, B. Cardiac abnormalities, C. History of thrombo-embolism, D. Nursing mothers
D: Nursing mothers
Answer: D: Nursing mothers 
Explanation: Contraindications for use of oral contraceptive pills (OCPs):