A company has a large dataset of proprietary documents and wants to build a Q&A system using a foundation model without exposing the documents to the model. Which approach is most appropriate?
RAG retrieves documents at query time without training on them.
Why this answer
Option A is correct because Retrieval-Augmented Generation (RAG) with Vertex AI Vector Search allows the system to retrieve relevant document chunks via embeddings without exposing the full documents to the foundation model. The model only sees the retrieved context in the prompt, ensuring proprietary data remains isolated and not used for training or memorization.
Exam trap
Google Cloud often tests the misconception that fine-tuning or prompt engineering can solve data privacy concerns, when in reality RAG is the only approach that keeps proprietary documents isolated from the model's training and inference pipeline.
How to eliminate wrong answers
Option B is wrong because a zero-shot model with context in the prompt still requires the entire document content to be included in the prompt, which exposes the proprietary data to the model and may exceed token limits. Option C is wrong because fine-tuning the model on the documents would directly expose the proprietary data to the model during training, risking memorization and data leakage. Option D is wrong because prompt engineering alone cannot retrieve specific information from a large dataset; it only instructs the model on how to respond, not where to find the data.