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 Q]: Problem: the diagonals of a rhombus are 10 cm and 12 cm . find its area ? 
Options: a ) 158 , b ) 60 , c ) 150 , d ) 123 , e ) 117
[EX A]: b

[EX Q]: Problem: what is the radius of the incircle of the triangle whose sides measure 5 , 12 and 13 units ? 
Options: ['a ) 2 units', 'b ) 12 units', 'c ) 6.5 units', 'd ) 6 units', 'e ) 7.5 units']
[EX A]: a

[EX Q]: Problem: some students are standing in a circle in which 6 th and the 16 th student are standing opposite to each other . find how many students were present there . 
Options: ['a ) 10', 'b ) 15', 'c ) 20', 'd ) 25', 'e ) 30']
[EX A]:
c