Which best explains whether a triangle with side lengths 5 cm, 13 cm, and 12 cm is a right triangle?

The triangle is a right triangle because 5^2 + 12^2 = 13^2.
The triangle is not a right triangle because 5 + 13 > 12.
The triangle is not a right triangle because 5^2 + 13^2 > 12^2.
The triangle is not a right triangle because 5 + 12 > 13.