The domain of $$f(x) = \frac{\cos^{-1}\left(\frac{x^2 - 5x + 6}{x^2 - 9}\right)}{\log(x^2 - 3x + 2)}$$ is

A

$$x \in \left[-\frac{1}{2}, 1\right) \cup (2, \infty) - \{3\}$$

B

$$x \in \left[-\frac{1}{2}, 1\right] \cup (2, \infty) - \{3\}$$

C

$$x \in \left(-\frac{1}{2}, 1\right) \cup [2, \infty) - \{3\}$$

D

$$x \in \left[-\frac{1}{2}, 1\right) \cup [2, \infty) - \{3\}$$