If x and y are two numbers having opposite signs, and $$x^{2}:y^{2}=16:81$$, then what is the value of $$\frac{3x+4y}{2x-3y}$$?

A

$$\frac{12}{25}$$

B

$$-\frac{27}{40}$$

C

$$-\frac{24}{35}$$

D

$$\frac{48}{35}$$