Step 1: Set up the integral for the area.
To find the area, we need to integrate the given function from 0 to the point where it intersects the x-axis. First, solve for the x-intercepts of the curve by setting \( y = 0 \).
\[
0 = 4x - x^2 \quad \Rightarrow \quad x(4 - x) = 0
\]
Thus, the x-intercepts are at \( x = 0 \) and \( x = 4 \).
Step 2: Integrate the function.
Now, integrate the function \( y = 4x - x^2 \) from 0 to 4:
\[
\text{Area} = \int_0^4 (4x - x^2) \, dx
\]
Evaluating the integral, we get the area as \( \frac{32}{3} \) square units.
Step 3: Conclusion.
Thus, the area of the region is \( \frac{32}{3} \), corresponding to option (B).