In this task, you need to provide the correct option for a given problem from the provided options.

[EX Q]: Problem: hree number are in the ratio of 3 : 4 : 5 and their l . c . m . is 2400 . their h . c . f . is : 
Options: a ) 40 , b ) 50 , c ) 60 , d ) 70 , e ) 80
[EX A]: a

[EX Q]: Problem: 9 log 9 ( 7 ) = ? 
Options: a ) 1 , b ) 2 , c ) 7 , d ) 4 , e ) 5
[EX A]: c

[EX Q]: Problem: set a consists of the integers from 4 to 17 , inclusive , while set b consists of the integers from 6 to 20 , inclusive . how many distinct integers do belong to the both sets at the same time ? 
Options: a ) 5 , b ) 7 , c ) 8 , d ) 9 , e ) 12
[EX A]:
e