Please give some explains! Thank you!

3. Assume Node temp is currently set equal to head. Which of the following while loops could be used to iterate through each element of a linkedlist? a) while (head !=null) b) while (temp !=null) c) while (head !=null) d) while (head !=null) e) while (temp !=null) head- temp.getNext; temp= temp.getNext temp = temp.getNext head -head.getNext; head head.getNext; 4. Which of the following for-loops could replace the previous while loop that would start at head and go until temp= null? Here count is the numberof item in the list, tail is the last Node a) for(Node temp-head, intj=0;j