$\int_{0}^{a}$$\sqrt{\left(a^{2}-x^{2}\right)} d x$ এর মান কোনটি?

$\frac{\pi a^{2}}{4}$

$\frac{\pi \mathrm{a}^{2}}{3}$

$\frac{\pi \mathrm{A}^{2}}{5}$

$\frac{\pi \mathrm{a}^{2}}{7}$

$3 \pi a^{2}$