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

Problem: sum of two numbers is 63 . their difference is 1 / 8 of their sum . their l . c . m is 
Options: a ) 231 , b ) 153 , c ) 351 , d ) 345 , e ) 355
c

Problem: 5 / 4 of all married couples have more than one child . 2 / 5 of all married couples have more than 3 children . what fraction of all married couples have 2 or 3 children ? 
Options: a ) 1 / 5 , b ) 1 / 4 , c ) 17 / 20 , d ) 3 / 5 , e ) it can not be determined from the given information .
c

Problem: find a sum for 1 st 7 prime number ' s ? 
Options: a ) 25 , b ) 28 , c ) 58 , d ) 34 , e ) 36

c