A. MQTT (Message Queuing Telemetry Transport)
B. CoAP
C. HTTP/2
D. UDP (User Datagram Protocol)

Solution

A. MQTT (Message Queuing Telemetry Transport)

Explanation

<p>MQTT (Message Queuing Telemetry Transport)</p><p>Designed for low-bandwidth, high-latency, or unstable networks</p><p>Uses publish/subscribe messaging pattern</p><p>Ideal for constrained devices (low power, low memory)</p><p>Enables real-time, bidirectional communication (device ↔ cloud)</p>