Task: Question Answering
Input (English): Problem: the average salary of all the workers in a workshop is $ 8000. the average salary of 7 technicians is $ 12000 and the average salary of the rest is $ 6000. the total number of workers in the shop is ?
Options: a. 15, b. 18, c. 21, d. 25, e. 31
Output (English): c