Answer:
A
Explanation:
Use Pythagorean Theorem, which is for side lengths of right triangles.
a^2 + b^2 = c^2 (c is the hypotenuse)
Common combination is 3-4-5. Just by looking at the answers, I can see A is 3-4-5 except everything is multiplied by 2.
B is wrong. It would be 5-12-13 if it were a RT.
C is wrong. 3-4-5
D is wrong. 4 + 25 = 49 is not an equation.