(d)
$S = {(\alpha \bullet 1 + \beta \bullet 1 + \gamma \bullet 1)}^{n} = {(\alpha + \beta - \gamma)}^{n}$
$\therefore\ \lim_{n \rightarrow \infty}{\frac{s}{\left\{ S^{\frac{1}{n}} + 1 \right\}^{n}} = \lim_{n \rightarrow \infty}{\left( \frac{\alpha + \beta - \gamma}{\alpha + \beta - \gamma + 1} \right)^{n} = 0}}$
$(\because\ \alpha + \beta - \gamma + 1 > \alpha + \beta - \gamma)$