Given the task definition and input, reply with output. In this task, you need to provide the correct option for a given problem from the provided options.

Problem: two sacks together contained 40 kilograms of sugar . if after 1 kilogram of sugar was taken from the first sack and poured into the second the weight of the sugar in the first sack became 60 % the weight of the sugar in the second , what was the original difference in the weights of the sacks ?
Options: a ) 4 , b ) 6 , c ) 8 , d ) 10 , e ) 12
c