In this task, you need to provide the correct option for a given problem from the provided options.

Q: Problem: what is the units digit of 26 ! + 50 ! + 4 ! + 4 ! ? 
Options: a ) 8 , b ) 6 , c ) 4 , d ) 2 , e ) 0

A: a
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Q: Problem: what is the greatest positive integer r such that 3 ^ r is a factor of 9 ^ 10 ? 
Options: a ) r = 5 , b ) r = 9 , c ) r = 10 , d ) r = 20 , e ) 30

A: d
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Q: Problem: the number of stamps that p and q had were in the ratio of 7 : 3 respectively . after p gave q 13 stamps , the ratio of the number of p ' s stamps to the number of q ' s stamps was 5 : 4 . as a result of the gift , p had how many more stamps than q ? 
Options: a ) 10 , b ) 25 , c ) 40 , d ) 65 , e ) 90

A:
a
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