Choose the correct option with respect to the statements $A$ and $B$:
$(A)$: When no electric field is applied across a conductor,the path of free electrons between two successive collisions in it is straight.
$(B)$: When an electric field is applied across a conductor,the drift velocity of electrons is independent of time.

• A
  $A$ and $B$ are true
• B
  $A$ is true and $B$ is false
• C
  $A$ is false and $B$ is true
• D
  $A$ and $B$ are false