Step 1: Understanding the current amplifier circuit.
In the given circuit with an ideal current amplifier, the feedback capacitance \( C_f \) and the input capacitance \( C_c \) determine the current gain. The current gain of a current amplifier is the ratio of the output current to the input current, which depends on the ratio of these capacitances.
Step 2: Analyzing the options.
- (A) \( \frac{C_f}{C_c} \): This is not the correct expression for the current gain.
- (B) \( \frac{-C_f}{C_c} \): This is also incorrect since the negative sign is not applicable in this case.
- (C) \( \frac{C_c}{C_f} \): This is the correct expression for the current gain in the given ideal current amplifier circuit.
- (D) \( \frac{-C_c}{C_f} \): This is incorrect for similar reasons as (B). Step 3: Conclusion.
The correct answer is (C), \( \frac{C_c}{C_f} \), which represents the current gain of the circuit.