Task: Question Answering
Input (English): Problem: jane and ashley take 20 days and 10 days respectively to complete a project when they work on it alone . they thought if they worked on the project together , they would take fewer days to complete it . during the period that they were working together , jane took an eight day leave from work . this led to jane ' s working for four extra days on her own to complete the project . how long did it take to finish the project ? 
Options: a ) 12 days , b ) 15 days , c ) 16 days , d ) 18 days , e ) 20 days
Output (English): a