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

Ex Input:
Problem: what is the area of a square field whose diagonal of length 16 m ? 
Options: a ) 128 , b ) 289 , c ) 200 , d ) 112 , e ) 178

Ex Output:
a


Ex Input:
Problem: 36 people { a 1 , a 2 , . . . , a 36 } meet and shake hands in a circular fashion . in other words , there are totally 36 handshakes involving the pairs , { a 1 , a 2 } , { a 2 , a 3 } , . . . , { a 35 , a 36 } , { a 36 , a 1 } . then size of the smallest set of people such that the rest have shaken hands with at least one person in the set is 
Options: ['a ) 11', 'b ) 12', 'c ) 13', 'd ) 15', 'e ) 18']

Ex Output:
b


Ex Input:
Problem: you buy a piece of land with an area of â ˆ š 400 , how long is one side of the land plot ? 
Options: a ) 28 , b ) 29 , c ) 30 , d ) 20 , e ) 32

Ex Output:

d