The area enclosed by the parabola ay = 3(a2 – x2) and the x- axis is

The parabola cuts the x-axis at points (–a, 0) and (a, 0).

$A = \int\limits_{-a}^ay\,dx=2\frac{3}{a}\int\limits_{0}^a(a^2-x^2)dx$

= 4a² sq. units.

Hence (A) is the correct answer.