To find the numbers that must be excluded from the domain of the rational expression \( \frac{4}{x+8} \), we need to identify any values of \( x \) that would make the denominator equal to zero, since division by zero is undefined.
Set the denominator equal to zero:
\[ x + 8 = 0 \]
Solving for \( x \), we get:
\[ x = -8 \]
Thus, the number that must be excluded from the domain is -8.
So, the correct choice would be:
A. The number(s) -8