The correct answer is C. Carrier sense multiple access with collision avoidance (CSMA-CA).
Carrier sense multiple access (CSMA) is a method of medium access control (MAC) in which a node senses the presence of a carrier on the medium before attempting to transmit. If the medium is busy, the node waits until it is idle before transmitting.
Carrier sense multiple access with collision detection (CSMA-CD) is a method of MAC in which a node senses the presence of a carrier on the medium before attempting to transmit. If the medium is busy, the node waits until it is idle before transmitting. If two nodes transmit at the same time, a collision occurs and both nodes will detect the collision and back off for a random amount of time before attempting to transmit again.
Carrier sense multiple access with collision avoidance (CSMA-CA) is a method of MAC in which a node senses the presence of a carrier on the medium before attempting to transmit. If the medium is busy, the node waits until it is idle before transmitting. If the medium is idle, the node will transmit after a random amount of time. This is done to avoid collisions.
IEEE 802.15.4 is a standard for low-power, short-range wireless personal area networks (WPANs). It is used in a variety of applications, including home automation, industrial automation, and medical devices. IEEE 802.15.4 uses CSMA-CA for accessing the channel.
CSMA-CA is a more efficient method of MAC than CSMA-CD. This is because CSMA-CA avoids collisions by having nodes transmit after a random amount of time. This prevents two nodes from transmitting at the same time and causing a collision.
CSMA-CA is also a more scalable method of MAC than CSMA-CD. This is because CSMA-CA can support more nodes on the network without causing collisions. This is because nodes transmit after a random amount of time, which spreads out the transmissions and prevents collisions.