The answer would be C. The triangle in question is NOT a right triangle.
For one thing, remember that a right triangle has a HYPOTENUSE, which is the LONGEST side. This shows that not all the sides has the same length. Also, remember the Pythagorean theorem:
c² = a² + b²
This means that they cannot all be equal.
If a triangle has 3 equal sides, then the triangle is an equilateral triangle.
