Step 1: Using the standard area formula for an ellipse.
The area of an ellipse is given by: \[ A = \pi a b \] where \( a^2 = 16 \Rightarrow a = 4 \) and \( b^2 = 9 \Rightarrow b = 3 \).
Step 2: Calculating the area.
\[ A = \pi (4)(3) = 12\pi \] Thus, the correct answer is (A).
Let \( f : \mathbb{R} \to \mathbb{R} \) be a twice differentiable function such that \( f(x + y) = f(x) f(y) \) for all \( x, y \in \mathbb{R} \). If \( f'(0) = 4a \) and \( f \) satisfies \( f''(x) - 3a f'(x) - f(x) = 0 \), where \( a > 0 \), then the area of the region R = {(x, y) | 0 \(\leq\) y \(\leq\) f(ax), 0 \(\leq\) x \(\leq\) 2\ is :