For a real number $r$, define $A_r=\left\{r^2\right\}, B_r$ as the closed interval $[r-1, r+1]$ and $C_r$ as the interval $(r, \infty)$. For $S=\{1,2,4\}$, determine
(a) $\bigcup_{\alpha \in S} A_\alpha$ and $\bigcap_{\alpha \in S} A_\alpha$
(b) $\bigcup_{\alpha \in S} B_\alpha$ and $\bigcap_{\alpha \in S} B_\alpha$
(c) $\bigcup_{\alpha \in S} C_\alpha$ and $\bigcap_{\alpha \in S} C_\alpha$.