$\int \sqrt{a^{2}-x^{2}} d x=$ কত ?

$\ln \left|\frac{a+x}{a-x}\right|+c$

$\ln \left|\frac{a-x}{a+x}\right|$

$\frac{x}{2} \sqrt{a^{2}-x^{2}}+\frac{a^{2}}{2} \sin ^{-1} \frac{x}{a}+c$

$\frac{a}{2} \sqrt{a^{2}-x^{2}}+\frac{x^{2}}{2} \sin ^{-1} \frac{x}{a}+c$