Choose the One Alternative That Best Completes the Statement or Answers

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
Find the domain of the composite function f ° g.
- $$f ( x ) = \frac { 1 } { x - 7 } ; \quad g ( x ) = \sqrt { x - 1 }$$

A) $\{ x \mid x \geq 1 , x \neq 7 \}$
B) $\{ x \mid x \geq 1 , x \neq 7 , x \neq 50 \}$
C) $\{ x \mid x$ is any real number $\}$
D) $\{ x \mid x \geq 1 , x \neq 50 \}$