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: Dental
Student t test is: 
Select and explain. 
A. Parametric test based on average, B. Non parametric test based on average, C. Parametric test based on variance, D. Non parametric test based on variance
A: Parametric test based on average
Answer: A: Parametric test based on average 
Explanation: None