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

Problem: in what ratio must a grocer mix two varieties of pulses costing rs . 15 and rs . 20 per kg respectively so as to get a mixture worth rs . 16.50 per kg ? 
Options: a ) 3 : 7 , b ) 5 : 7 , c ) 7 : 3 , d ) 7 : 5 , e ) none
c

Problem: how many factors of 2475 are odd numbers greater than 1 ? 
Options: a ) 3 , b ) 4 , c ) 17 , d ) 6 , e ) 7
c

Problem: find the fraction which has the same ratio to 2 / 6 that 3 / 4 has to 1 / 2 
Options: a ) 1 / 2 , b ) 2 / 5 , c ) 6 / 8 , d ) 9 / 4 , e ) 7 / 5

a