Rational Numbers are...

$$\frac{2}{3}$$

$$0.33333...$$

Which of the following numbers is rational?

$$\sqrt[]{6}\ \cdot\ \sqrt[]{6}$$

$$\sqrt[]{5}\ +\ \sqrt[]{4}$$

$$\left(\frac{1}{2}\right)\cdot\left(0.5781029...\right)$$

$$\sqrt[]{4}\ +\ \sqrt[]{16}$$

$$\sqrt[]{50}+\ \sqrt[]{2}$$