Explanation:

- Understanding Transistor Parameters:

- In the Common Emitter configuration, the transistor's performance is often characterized by various resistances and currents.

- Output dynamic resistance: This is defined as the ratio of the change in collector-emitter voltage to the resulting change in collector current at a constant base current.

- Parameter Analysis:

- Input dynamic resistance: Involves changes in input voltage and input current, not applicable here.

- Output dynamic resistance: Correct, as it relates specifically to changes in output voltage and current in this transistor configuration.

- Output emitter Current: Incorrect, this term does not describe a resistance ratio.

- Input emitter Current: Incorrect, also unrelated to the specified resistance ratio.

- The correct answer is Output dynamic resistance from Option 2.