Which of the following statements are correct with respect to $DNA$ separation, isolation and visualization?
$A$. The cutting of $DNA$ is done by molecular scissors.
$B$. The $DNA$ fragments separate according to their size in an agarose gel, upon electrophoresis.
$C$. The separated $DNA$ fragments can be seen without staining when exposed to $UV$ light.
$D$. The separated $DNA$ fragments, when stained with ethidium bromide, can be seen in visible light.
Choose the correct answer from the options given below:

• A
  $(1)$ $A$ and $B$ only
• B
  $(2)$ $B$ and $D$ only
• C
  $(3)$ $A$ and $D$ only
• D
  $(4)$ $B$ and $C$ only