The problem asks for the value of $f(4)$ given the function:

$f(x) = x^2 + 5x - 6$

To solve for $f(4)$, we substitute $x = 4$ into the function:

$f(4) = 4^2 + 5(4) - 6$

Now, calculate step by step:

$4^2 = 16$ $5(4) = 20$ $f(4) = 16 + 20 - 6 = 36 - 6 = 30$

So, $f(4) = 30$.

The correct answer is $\boxed{B}$.

Do you have any questions or want further details?

Here are some related questions you might want to explore:

1. What is the general form of a quadratic function?
2. How do you find the vertex of a quadratic function?
3. What are the roots of the function $f(x) = x^2 + 5x - 6$?
4. How does the graph of a quadratic function look?
5. How do we solve quadratic equations using the quadratic formula?

Tip: Always substitute carefully and follow the order of operations when evaluating functions.