Task: Question Answering
Input (English): Question: If 'A' means '-', 'B' means '/', 'C' means '+', and 'D' means 'X' then
Find the value of the following:
21 B 7 C 9 D 10 A 13

 Option A: 80

 Option B: 40

 Option C: 60

 Option D: 70

 Option E: 50
Output (English): Option A