Why Must an Agarose Gel Be Placed in a Buffer

Multiple Choice

Why must an agarose gel be placed in a buffer solution for DNA gel electrophoresis?

A) Ions in the buffer conduct the electric current needed to move the DNA fragments in the gel matrix. 
B) The DNA fragments will disintegrate unless there is a buffer present to prevent this from happening.
C) Even distilled, autoclaved water has a high number of DNases in it that would destroy the DNA.
D) The buffer contains phosphates, and the DNA fragments must be phosphorylated before they move in agarose.
E) DNA cannot be detected unless buffer is added to the system; the buffer colors the DNA fragments for visualization.