To find the degree of the polynomial \( f(x) = 8(x - 1)(x + 3)^5 \), we need to determine the degree of each factor:
- \( (x - 1) \) is a linear factor, and its degree is 1.
- \( (x + 3)^5 \) is a polynomial raised to the power of 5, and its degree is 5.
The total degree of the polynomial \( f(x) \) is the sum of the degrees of its individual factors. Therefore, the degree is:
\[ 1 + 5 = 6 \]
So, the degree of \( f(x) \) is \( 6 \).
The correct response is 6.