Answer: C
Explanation:
The problem says that one side of a right triangle has a length of 12 feet.
This means that when you use the Pythagorean theorem on the triangle, it should work.
The lengths that the Pythagorean theorem doesn't work are the ones that don't work.
I is true.
5^2+12^2=13^2
II is also true.
63+9^2=12^2
III is false, however. The Pythagorean theorem doesn't work.
Therefore, the answer is C. I and II only.