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

Q: Problem: what is the measure of the radius of the circle inscribed in a triangle whose sides measure 4 , 11 and 12 units ? 
Options: ['a ) 1.6 units', 'b ) 6 units', 'c ) 3 units', 'd ) 5 units', 'e ) 12 units']

A: a
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Q: Problem: if the sum of a number and its square is 72 , what is the number ? 
Options: a ) 15 , b ) 26 , c ) 8 , d ) 91 , e ) none of these

A: c
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Q: Problem: a 15 by 20 rectangle is inscribed in circle . what is the circumference of the circle ? 
Options: a ) 5 π , b ) 10 π , c ) 15 π , d ) 20 π , e ) 25 π

A:
e
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