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: Medicine
Sinus tachycardia is seen in 
Select and explain. 
A. Beta blocker therapy, B. Athletes, C. Hypothyroidism, D. Severe anaemia
D: Severe anaemia
Answer: D: Severe anaemia 
Explanation: None