(a)
Using AM$>$GM [$\therefore a,b\ and\ c\ are\ distinct$]
$\therefore\frac{a^{2} + b^{2} + c^{2}}{3} > \left( a^{2}b^{2}c^{2} \right)^{1/3}\$
$\Rightarrow \ \ 3\left( a^{2}b^{2}c^{2} \right)^{\frac{1}{3}}\ \ \ \ \ \ \lbrack\therefore a^{2} + b^{2} + c^{2} = 1\ given\rbrack$