$$(4x + 3y)^{2} + (4x - 3y)^{2}$$ is equal to:

A

$$16x^{2} - 9y^{2}$$

B

$$32x^{2} + 18y^{2}$$

C

$$16x^{2} + 9y^{2}$$

D

$$32x^{2} + 9y^{2}$$