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'.

Q: Problem: r is the set of positive even integers less than 20 , and s is the set of the squares of the integers in r . how many elements does the intersection of r and s contain ? 
Options: ['a ) none', 'b ) two', 'c ) three', 'd ) five', 'e ) seven']

A: c
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Q: Problem: when the perimeter of a regular polygon is divided by 5 , the length of a side is 25 . what is the name of the polygon ? what is the perimeter ? 
Options: ['a ) 125', 'b ) 126', 'c ) 127', 'd ) 128', 'e ) 129']

A: a
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Q: Problem: the radius of a semi circle is 6.3 cm then its perimeter is ? 
Options: a ) 32.9 , b ) 32.4 , c ) 32.2 , d ) 32.1 , e ) 32.7

A:
b
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