Let the line x + y = 1 meet the axes of x and y at A and B, respectively. A right angled triangle AMN is inscribed in the triangle OAB , where O is the origin and the points M and N lie on the lines OB and AB, respectively. If the area of the triangle AMN is $$\frac{4}{9}$$ of the area of the triangle OAB and AN : NB = $$\lambda$$:1 , then the sum of all possible value(s) of is $$\lambda$$ :

A

2

B

$$\frac{5}{2}$$

C

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

D

$$\frac{13}{6}$$