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

Problem: the ratio of number of boys and girls in a school is 2 : 5 . if there are 420 students in the school , find the number of girls in the school ? 
Options: a ) 150 , b ) 250 , c ) 300 , d ) 370 , e ) 280
c

Problem: if both 5 ^ 2 and 3 ^ 3 are factors of n x ( 2 ^ 5 ) x ( 12 ^ 2 ) x ( 7 ^ 3 ) x ( 10 ) , what is the smallest possible positive value of n ? 
Options: a ) 15 , b ) 45 , c ) 75 , d ) 125 , e ) 150
a

Problem: the ratio of the present age of two brothers is 1 : 2 and 5 years back , the ratio was 1 : 3 . what will be the ratio of their ages after 5 years ? 
Options: a ) 3 : 9 , b ) 3 : 0 , c ) 3 : 5 , d ) 3 : 2 , e ) 3 : 1

c