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: the ratio of 2 numbers is 3 : 4 and their h . c . f . is 4 . their l . c . m . is ? 
Options: a ) 20 , b ) 24 , c ) 48 , d ) 36 , e ) 60

c