In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: a ratio between two numbers is 7 : 9 and their l . c . m . is 189 . the second number is
Options: a ) 35 , b ) 25 , c ) 20 , d ) 27 , e ) none
d