public static void main(String args[]){ try{ HashSet hashSet = new HashSet(); String one = null; hashSet.add(one); hashSet.add("two"); hashSet.add("Three"); Iterator iterator = hashSet.iterator(); while(iterator.hasNest()) { System.out.println(iterator.nest()); }}} options : a. null b. two c. compilation fail d. null pointer exception two three three | 0 |