We are given the function $f(x) = 4x - 12$, and asked to find $f(2)$.

To solve for $f(2)$, substitute $x = 2$ into the function:

$f(2) = 4(2) - 12 = 8 - 12 = -4$

So, the correct answer is $\boxed{A. -4}$.

Would you like further details or explanations on this?

Here are five related questions:

1. What is the value of $f(3)$ for the same function?
2. If $f(x) = 4x - 12$, what is the inverse function $f^{-1}(x)$?
3. How do you determine if a function is linear or nonlinear?
4. What is the slope and y-intercept of the function $f(x) = 4x - 12$?
5. Can you solve for $f(x) = 0$ and find the value of $x$?

Tip: Always check your substitution carefully when plugging values into a function to avoid small calculation errors.