Task: Question Answering
Input (English): Problem: points a , b , c , and d , in that order , lie on a line . if ab = 2 cm , ac = 4 cm , and bd = 6 cm , what is cd , in centimeters ? 
Options: a ) 1 , b ) 2 , c ) 3 , d ) 4 , e ) 5
Output (English): d