If $$[\surd(a^2 + b^2 + ab)] + [\surd(a^2 + b^2 - ab)] = 1$$, then what is the value of $$(1 - a^2)(1 - b^2)$$?

A

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

B

$$\frac{4}{7}$$

C

$$\frac{5}{4}$$

D

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