$4.(1$ point$)$ Suppose that b and i are declared as follows:

enum $\backslash \{$FALSE$,$ TRUE$\backslash \}$ b ;

int i;

Identify which of the following statements are legal and$/$or "safe' $($always yield a meaningful result$).$ Justify.

$($a$)$ b $=$ FALSE;

$($b$)$ b $=$ i;

$($c$)$ b$++$;

$($d$)\backslash (\backslash$mathrm$\{$i$\}=\backslash$mathrm$\{$b$\}\backslash )$;

$($e$)\backslash (\backslash$mathrm$\{$i$\}=2*\backslash$mathrm$\{$~b$\}+1\backslash )$;

$5.(1$ point$)$ Suppose that f and p are declared as follows:

$```$

struct $\{$

union $\{$

char a b;

int c;

$\}$ d;

int e$[5]$;

$\}$ f$,*$p$=$&f;

$```$

Which of the following statements are legal? Why? If not legal, correct them.

$($a$)\backslash (\backslash$mathrm$\{$p$\}->\backslash$mathrm$\{$b$\}=\backslash )\text{'}\text{'}$;

$($b$)$ p$->$e $[3]=10$;

$($c$)(*$p$).$d$.$a $=\text{'}*\text{'}$;

$($d$)\backslash (\backslash$mathrm$\{$p$\}->\backslash$mathrm$\{$d$\}->\backslash$mathrm$\{$c$\}=20\backslash )$;

$6.(1$ point$)$ The following loop is supposed to delete all nodes from a linked list and release the memory that they occupy. Unfortunately, the loop is incorrect. Explain what's wrong with it and show how to fix the bug.

$```$

for $($p $=$ first; p $!=$ NULL; p $=$ p$->$next$)$

free$($p$)$;

$```$