The device which is a combination of a receiver and a transmitter is

Options

A. Amplifier
B. Repeater
C. Transducer
D. Modulator

Explanation

To solve the question regarding the device that is a combination of a receiver and a transmitter, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- A **transmitter** is a device that sends out signals, typically in the form of electromagnetic waves.
- A **receiver** is a device that receives these signals and converts them back into a usable form.

2. **Identifying the Combination**:
- The question asks for a device that combines both functions: receiving and transmitting signals.

3. **Exploring Examples**:
- Common devices that perform both functions include radios, walkie-talkies, and repeaters. However, the term that specifically refers to a device that both receives and transmits signals simultaneously is crucial.

4. **Defining the Correct Term**:
- The device that fits the description of combining a receiver and a transmitter is known as a **transceiver**. A transceiver can both send and receive signals, making it a crucial component in communication systems.

5. **Conclusion**:
- Therefore, the answer to the question is that the device which is a combination of a receiver and a transmitter is a **transceiver**.

### Final Answer:
The device which is a combination of a receiver and a transmitter is a **transceiver**.