$A$ variable,opposite external potential $(E_{ext})$ is applied to the cell $Zn | Zn^{2+} (1 \ M) || Cu^{2+} (1 \ M) | Cu$ of potential $1.1 \ V$. When $E_{ext} < 1.1 \ V$ and $E_{ext} > 1.1 \ V$,respectively,electrons flow from:

• A
  anode to cathode in both cases
• B
  cathode to anode and anode to cathode
• C
  anode to cathode and cathode to anode
• D
  cathode to anode in both cases