The question asks to identify the characteristics of the Common Collector (CC) configuration, also known as the emitter follower.

CC Configuration Key Features

• Input Impedance ($Z_{in}$): The CC configuration offers a very high input impedance. This is primarily because the input signal drives the base-emitter junction, which has a high dynamic resistance, amplified by the transistor's current gain.
• Voltage Gain ($A_v$): The voltage gain is approximately unity ($A_v \approx 1$), slightly less than 1. It acts as a voltage follower, meaning the output voltage closely mimics the input voltage.
• Current Gain ($A_i$): The CC configuration provides a high current gain. The current gain is typically close to $\beta + 1$, where $\beta$ is the common-emitter current gain.

Analysis of Options

Based on the features:

• Option 1 correctly states highest input impedance and highest current gain.
• Option 2 is incorrect because while input impedance is high, the voltage gain is approximately 1, not the highest.
• Option 3 is incorrect because the input impedance is high, not low.
• Option 4 is incorrect; it describes characteristics more aligned with Common Base (low $Z_{in}$) or Common Emitter (high $A_v$) configurations.

Therefore, the defining features of the CC configuration are its high input impedance and high current gain.