Task: Question Answering
Input (English): Question: Three math classes: X, Y, and Z, take an algebra test.
The average score in class X is 83.
The average score in class Y is 76.
The average score in class Z is 85.
The average score of all students in classes X and Y together is 79.
The average score of all students in classes Y and Z together is 81.
What is the average score for all the three classes, taken together?

 Option A: 81

 Option B: 81.5

 Option C: 82

 Option D: 84.5

 Option E: None of these
Output (English): Option B