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'.

Ex Input:
Problem: a cyclist rides a bicycle 7 km at an average speed of 10 km / hr and again travels 10 km at an average speed of 7 km / hr . what is the average speed for the entire trip ?
Options: a ) 7.59 , b ) 7.79 , c ) 7.99 , d ) 8.19 , e ) 8.39

Ex Output:
c

Ex Input:
Problem: 123 : 36 : : 221 : ?
Options: a ) 52 , b ) 69 , c ) 72 , d ) 25 , e ) 32

Ex Output:
d

Ex Input:
Problem: joan and karl each bought a telescopes and the sum of their purchases was $ 400 . if twice of what joan paid was $ 74 more than what karl paid , what did joan pay for her telescope ?
Options: a ) $ 150 , b ) $ 152 , c ) $ 154 , d ) $ 156 , e ) $ 158

Ex Output:
e