Comprehensive Detailed Explanation
Active learning in Language Understanding (LUIS / Conversational Language Understanding) works by collecting real user queries sent to your prediction endpoint.
By setting log=true in the prediction endpoint query, these user utterances are stored in the LUIS service.
The logged utterances can then be reviewed in the Review endpoint utterances page of the LUIS portal, where you can relabel and retrain the model. This enables the active learning loop.
Why not the others?
A). show-all-intents=true: This simply forces the endpoint to return all intents, not related to active learning.
B). Enable speech priming: Used for improving speech-to-text accuracy, unrelated to LUIS active learning.
D). Enable sentiment analysis: Adds sentiment scores to prediction output, not related to active learning.
Reference:
LUIS active learning with endpoint utterances
utterances#log-user-queries-to-enable-active-learning