For transistor amplifier the voltage gain
(a) remains constant for all frequencies
(b) is high at high and low frequencies
(c ) is low at high and low frequencies and constant in the middle frequency range
(d) none of these

Explanation

To determine the correct answer regarding the voltage gain of a transistor amplifier in relation to frequency, we can analyze the characteristics of transistor amplifiers:

### Step-by-Step Solution:

1. **Understanding Voltage Gain**: The voltage gain of a transistor amplifier is defined as the ratio of the output voltage to the input voltage. It is a measure of how much the amplifier increases the voltage of a signal.

2. **Frequency Response of Amplifiers**: Transistor amplifiers have a frequency response that varies with frequency. Generally, the voltage gain is not constant across all frequencies.

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