Answer: c)
Explanation:
This can be done through trial-and-error. Use the pythagoreas' theorem 
 and if the left side of the equation is equal to the right, that is the answer.
 and if the left side of the equation is equal to the right, that is the answer.
(Do take note that c is the longest side.)
a)


Since 
 , a) is wrong.
, a) is wrong.
b)

Since 
 , b) is wrong.
, b) is wrong.
c) (answer)

Since 
 , c) is correct.
, c) is correct.
d)

Since 
 , d) is wrong.
, d) is wrong.