Observe the triangle is a right triangle.

Hypotenuse of the triangle is $\"\"$ and other two sides are $\"\"$ .

Apply the Pythagorean theorem

The square of hypotenuse is equal to the sum of the squares of the other two sides.

$\"\"$

Take square root each side.

$\"\"$

The value of $\"\"$ in terms of $\"\"$ is $\"\"$ .

Option B is correct.