[Solved] This Python code snippet attempts to publish a message with QoS 1: client.publish('topic', 'data', qos=3) What is the error in this code? | Raspberry Pi

Raspberry Pi - MQTT for IoT

This Python code snippet attempts to publish a message with QoS 1:

client.publish('topic', 'data', qos=3)

What is the error in this code?

AQoS level 3 is invalid in MQTT.

BThe topic name is incorrect.

CThe message payload must be bytes, not string.

DThe publish method requires a callback parameter.

Step-by-Step Solution

Solution:

Step 1: Check valid QoS levels in MQTT
MQTT supports QoS levels 0, 1, and 2 only.
Step 2: Identify invalid QoS usage
Using qos=3 is invalid and will cause an error or be ignored.
Final Answer:
QoS level 3 is invalid in MQTT. -> Option A
Quick Check:
Valid QoS levels: 0, 1, 2 only [OK]

Quick Trick: MQTT QoS levels only 0, 1, or 2 [OK]

Common Mistakes:

MISTAKES

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This Python code snippet attempts to publish a message with QoS 1: