C is 3rd from the top and D is 4th from the bottom in a class of 15 students. What is the total number of students in the class?
Answer: A. 15
If C is 3rd from the top, then there are 12 students below C. If D is 4th from the bottom, then there are 11 students above D. Therefore, total students = 3 + 11 + 1 = 15.