Answer:
4th choice, 20, 21, 29 would be the answer.
Step-by-step explanation:
Pythagorean Theorem: a^2 + b^2 = c^2
a= 20, b= 21, c= 29 ( c has to be the C, hypotenuse, because it is the longest)
therefore,
20^2 + 21^2 = 29^2
into
400 + 441 = 841,
which is true, makes the Pythagorean Theorem work.
