Q: In this task, you need to provide the correct option for a given problem from the provided options.
Problem: the ratio of 2 numbers is 3 : 7 and their h . c . f . is 12 . their l . c . m . is ? 
Options: a ) 20 , b ) 24 , c ) 252 , d ) 136 , e ) 160
A:
c