What is the domain of the function $f(x)=\frac{x+1}{x^2-6 x+8}$ ?
Aall real numbers
Ball real numbers except -1
Call real numbers except -4 and -2
Dall real numbers except 2 and 4
Aall real numbers
Ball real numbers except -1
Call real numbers except -4 and -2
Dall real numbers except 2 and 4