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: what is the least number of square tiles required to pave the floor of a room 11 m 50 cm long and 1 m 50 cm broad ? 
Options: a ) 724 , b ) 804 , c ) 69 , d ) 844 , e ) none
Example Output: c

Example Input: Problem: a rectangular grassy plot 100 m . by 70 m has a gravel path 2.5 m wide all round it on the inside . find the cost of gravelling the path at 90 paise per sq . metre . 
Options: a ) rs . 700 , b ) rs . 708.50 , c ) rs . 732.50 , d ) rs . 742.50 , e ) none of these
Example Output: d

Example Input: Problem: a and b together can do a work in 2 days . a alone can do it in 12 days . what time b will take to do the work alone ? 
Options: a ) 2.4 days , b ) 8 days , c ) 1.2 days , d ) 1.0 days , e ) 5 days
Example Output:
a