C is ranked 2nd from the top and D is ranked 3rd from the bottom in a class of 15 students. What is the total number of students in the class?

Answer: A. 15
C's rank from the bottom is 15 - 2 + 1 = 14. D's rank from the bottom is 3, so 14 + 3 - 1 = 15 students in total.