Answer the following question given this paragraph: 

A unit cell is the smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire crystal. A crystal can be thought of as the same unit cell repeated over and over in three dimensions. The Figure below illustrates the relationship of a unit cell to the entire crystal lattice.


Q: What is the smallest portion of a crystal lattice?

 Choices:

- ionic cell

- function cell

- element cell

- unit cell

A:
unit cell
