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
Mean bone density amongst two groups of 50 people each is compared with each other. The test of significance used would be - 
Select and explain. 
A. Paired-t-test, B. Student t-test, C. Analysis of variance, D. Chi-Square test
B: Student t-test
Answer: B: Student t-test 
Explanation: None