When creating an array list$/$vector $($i$.$e$.,$ a dynamic array$),$ which of the following aspects are required? A variable to track the current number of elements in the array list. A variable to track the total capacity of the array list. The array should be allocated on the stack. The array should be allocated on the heap. A function to sort the elements in the array list. Automatically increasing the array's capacity when the size $=$ capacity by a predetermined formula such as doubling the capacity.