Answer:
D
Step-by-step explanation:
so basically to add up radicals you need to make the number inside the square root the same. what you have to do to do that is find squares inside the number as a factor.
13√80=13*2√20=13*2*2√5=52√5
3√125=3*5√5=15√5
√500=10√5
so all of them have 5 in the square root so you can add them up to equal 77√5