Task: Question Answering
Input (English): Problem: the cross - section of a water channel is a trapezium in shape . if the channel is 12 meters wide at the top and 8 meters wide at the bottom and the area of cross - section is 700 square meters , what is the depth of the channel ( in meters ) ? 
Options: ['a ) 50', 'b ) 60', 'c ) 70', 'd ) 80', 'e ) 90']
Output (English): c