ASuppose You Need to Store a List of Elements, If

Short Answer

a.Suppose you need to store a list of elements, if the number of elements in the program is fixed, what data structure should you use? (array, ArrayList, or LinkedList)
b.If you have to add or delete the elements at the beginning of a list, should you use ArrayList or LinkedList?
c.If most of operations on a list involve retrieving an element at a given index, should you use ArrayList or LinkedList?