Explanation

(c)
Since, $\alpha\ and\ \beta$ are the roots of $ax^{2} + bx + c = 0$.
Then, $\alpha + \beta = - \frac{b}{a}\ and\ \alpha\beta = \frac{c}{a}$
Let the roots of $cx^{2} + bx + a = 0\ be\ \alpha^{'},\ \beta^{'},$ then
$\alpha^{'} + \ \beta^{'} = - \frac{b}{c}\ and\ \alpha^{'}\beta^{'} = \frac{a}{c}$
Now, $\frac{\alpha + \beta}{\alpha\beta} = \frac{- \frac{b}{a}}{\frac{c}{a}} = \frac{- b}{c}$
$\Rightarrow \frac{1}{\alpha} + \frac{1}{\beta} = \alpha^{'} + \ \beta^{'}$
Hence, $\alpha^{'} = \frac{1}{\alpha}\ and\ \beta^{'} = \ \frac{1}{\beta}$