CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is a protocol used in Ethernet networks to control access to the shared communication medium. It is a contention-based protocol, meaning that multiple devices can attempt to transmit data at the same time, leading to collisions. The protocol allows devices to detect and resolve collisions, ensuring efficient and reliable communication.

The given statement that CSMA/CD is not suitable for a high propagation delay network like a satellite network (option C) is true. Here's an explanation of why this statement is correct:

1. Understanding CSMA/CD:
- CSMA/CD is a protocol used in Ethernet networks where devices listen to the medium before transmitting.
- If the medium is idle, a device can start transmitting immediately.
- If the medium is busy, the device waits for a predefined period and then retries.
- If two or more devices transmit simultaneously, a collision occurs, and the devices involved detect the collision.

2. High propagation delay in satellite networks:
- Satellite networks have high propagation delay due to the distance signals need to travel between Earth and the satellite.
- The time taken for a signal to propagate from the sender to the satellite and back to the receiver is considerable.
- During this propagation delay, devices in the network may continue to transmit, unaware of the ongoing transmission.

3. Impact on CSMA/CD:
- CSMA/CD relies on the ability of devices to detect collisions in real-time.
- In high propagation delay networks, the detection of collisions is delayed due to the time required for signals to propagate.
- This delay results in a longer time to detect collisions, leading to inefficient utilization of the network bandwidth.

4. Suitable alternatives for satellite networks:
- CSMA/CD is not suitable for satellite networks due to the high propagation delay.
- Instead, protocols like CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) are used in wireless networks, including IEEE 802.11 wireless LANs.
- CSMA/CA includes a mechanism for devices to request and reserve the medium before transmitting, reducing the likelihood of collisions.

In conclusion, CSMA/CD is not suitable for high propagation delay networks like satellite networks. The delay in detecting collisions due to the long propagation delay results in inefficient network utilization. Instead, protocols like CSMA/CA are used in such networks to avoid collisions and improve efficiency.