Answer:
B. The hypotenuse is square root 2 times as long as either leg.
Explanation:
The answer is B.
Let's use Pythagoras to prove it.

In this case since its an isoceles right triangle, a and b most be the same.
Let's say that the measure of the sides that are equal is x and the hypotenuse is h.
Pythagoras tells us the following:

Solving for h:

The hypotenuse is square root 2 times as long as the sides, in this case x wich could be any number.