Arrange the steps in agarose gel electrophoresis in the correct order.

1) Digest DNA with a restriction enzyme
2) Separate DNA by size on agarose gel
3) Stain DNA with ethidium bromide and visualize by UV-light

A) 1, 2, 3
B) 3, 2, 1
C) 2, 1, 3
D) 1, 3, 2