c
$\operatorname{Lim}_{x \rightarrow 0^{+}} f(x)=f(0)=\operatorname{Lim}_{x \rightarrow 0^{-}}(x)$
$\operatorname{Lim}_{x \rightarrow 0^{+}} \frac{\cos ^{-1}\left(1-x^{2}\right) \cdot \sin ^{-1}(1-x)}{x(1-x)(1+x)}$
$\operatorname{Lim}_{x \rightarrow 0^{+}} \frac{\cos ^{-1}\left(1-x^{2}\right)}{x \cdot 1 \cdot 1} \cdot \frac{\pi}{2}$
Let $1-x^{2}=\cos \theta$
$\frac{\pi}{2} \operatorname{Lim}_{ x \rightarrow 0^{+}} \frac{\theta}{\sqrt{1-\cos \theta}}$
$\frac{\pi}{2} \operatorname{Lim}_{\theta \rightarrow 0^{+}} \frac{\theta}{\sqrt{2} \sin \frac{\theta}{2}}=\frac{\pi}{\sqrt{2}}$
Now, $\operatorname{Lim}_{x \rightarrow 0^{-}} \frac{\cos ^{-1}\left(1-(1+x)^{2}\right) \sin ^{-1}(-x)}{(1+x)-(1+x)^{3}}$
$\operatorname{Lim}_{x \rightarrow 0^{-}} \frac{\frac{\pi}{2}\left(-\sin ^{-1} x\right)}{(1+x)(2+x)(-x)}$
$\operatorname{Lim}_{x \rightarrow 0^{-}} \frac{\frac{\pi}{2}}{1 \cdot 2} \cdot \frac{\sin ^{-1} x}{x}=\frac{\pi}{4}$
$\Rightarrow RHL \neq LHL$
Function can't be continuous
$\Rightarrow$ No value of $\alpha$ exist