What is the value of naList$[4]$ after the following code executes? int$[]$ naList $=$ new int$[6]$;

naList $[0]=5$;

naList $[1]=10$;

naList$[2]=15$;

naList$[3]=20$;

naList$[5]=30$

$25$

$30$

$20$

null

$0$