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

Problem: in measuring the sides of a rectangle , one side is taken 16 % in excess and other 5 % in deficit . find the error percentage in the area calculated from these measurements . 
Options: a ) 3.5 % , b ) 2.4 % , c ) 10.2 % , d ) 5 % , e ) 2.6 %
c

Problem: what positive number , when squared , is equal to the cube of the positive square root of 14 ? 
Options: a ) 64 , b ) 32 , c ) 8 , d ) 4 , e ) 2
d

Problem: what is the measure of the radius of the circle inscribed in a triangle whose sides measure 8 , 15 and 21 units ? 
Options: a ) 8.5 units , b ) 2.6 units , c ) 3 units , d ) 5 units , e ) 12 units

b