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
Ten readings of BP taken before and after treatment is studied by - 
Select and explain. 
A. Paired 't' test, B. 'Z' test, C. Students `t' test, D. Correlation test
A: Paired 't' test
Answer: A: Paired 't' test 
Explanation: None