In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: a worker earns $ 20 on the first day and spends $ 15 on the second day . the worker earns $ 20 on the third day and spends $ 15 on the fourth day . if this pattern continues , on which day will the worker first reach a net total of $ 90 ? 
Options: a ) 28 , b ) 29 , c ) 31 , d ) 34 , e ) 36
Example Output: b

Example Input: Problem: a 70 cm long wire is to be cut into two pieces so that one piece will be 2 / 3 th of the other , how many centimeters will the shorter piece be ? 
Options: a ) 35 , b ) 20 , c ) 28 , d ) 36 , e ) 30
Example Output: c

Example Input: Problem: a machine , working at a constant rate , manufactures 18 pens in 30 minutes . how many pens does it make in 1 hr 45 min ? 
Options: a ) 63 , b ) 65 , c ) 62 , d ) 60 , e ) 45
Example Output:
a