Choice D is the correct answer. For translations, moving to the right 5 units means you add 5 to x, and moving down 2 units means you subtract 2 from y. D is the only choice that accurately represents this.
Using the Pythagorean theorem (a² + b² = c²) you would end up with an equation like this: 36 + 64 = 100. You would then square root 100 and the answer would be 10 ft