Task: Question Answering
Input (English): Problem: the average of 9 observations was 9 , that of the 1 st of 4 being 10 and that of the last 4 being 8 . what was the 5 th observation ? 
Options: a ) 4 , b ) 5 , c ) 6 , d ) 7 , e ) 8
Output (English): d