If $$a + b + c = \frac{7}{12}, 3a - 4b + 5c = \frac{3}{4}$$ and $$7a - 11b - 13c = \frac{-7}{12}$$, then what is the value of $$a + c$$?

A

$$\frac{1}{2}$$

B

$$\frac{5}{12}$$

C

$$\frac{3}{4}$$

D

$$\frac{1}{4}$$