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: Pathology
Which of the following is a non-modifiable risk factor for CHD ? 
Select and explain. 
A. Diabetes, B. Smoking, C. Hypeension, D. Old age
D: Old age
Answer: D: Old age 
Explanation: Ans. is 'd' i.e., Old age Old age is a non-modifiable risk factor for atherosclerosis and coronary hea disease (CHD). Other three (given in question) are modifiable risk factors.