When a bipolar junction transistor is operating in the saturation mode, which one of the following statements is TRUE about the state of its collector-base $(CB)$ and the base-emitter $(BE)$ junctions?
1. The $CB$ junction is forward biased and the $BE$ junction is reverse biased.
2. The $CB$ junction is reverse biased and the $BE$ junction is forward biased.
3. Both the $CB$ and $BE$ junctions are forward biased.
4. Both the $CB$ and $BE$ junctions are reverse biased.