Tom' cat arranges the glass balls, in a particular 3D array, that two (I and II) continuous layer are not identical, but all (I and III) alternative layer are identical, this type of arrangement is known as:

Tom' cat arranges the glass balls, in a particular 3D array, that two

1.	Tom' cat arranges the glass balls, in a particular 3D array, that two (I and II) continuous layer are not identical, but all (I and III) alternative layer are identical, this type of arrangement is known as:
Answer» ANSWER :ABAB.... Type arrangement (UNIT CELL = HCP)