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

[EX Q]: Problem: among 300 students , 56 % study sociology , 44 % study mathematics and 40 % study biology . if 30 % of students study both mathematics and sociology , what is the largest possible number of students who study biology but do not study either mathematics or sociology ? 
Options: a ) 30 , b ) 90 , c ) 120 , d ) 172 , e ) 188
[EX A]: b

[EX Q]: Problem: the cost of 3 pens and 5 pencils is rs . 260 . also the cost of one pen and one pencil is in the ratio of 5 : 1 respectively . what is the cost of one dozen pens ? 
Options: a ) rs . 200 , b ) rs . 250 , c ) rs . 300 , d ) rs . 780 , e ) none of these
[EX A]: d

[EX Q]: Problem: two numbers are in the ratio 3 : 4 . if their l . c . m . is 60 . what is sum of the numbers ? 
Options: a ) 35 , b ) 56 , c ) 76 , d ) 84 , e ) 85
[EX A]:
a