A company has a large amount of unlabeled data.

Comprehensive and Detailed Explanation (AWS AI documents):

AWS machine learning fundamentals classify K-means as an unsupervised learning algorithm used to group unlabeled data into clusters based on feature similarity and distance metrics. Because the data is unlabeled and the goal is grouping rather than prediction, K-means is the most appropriate choice.

Why the other options are incorrect:

XGBoost is a supervised learning algorithm that requires labeled data.

DeepAR forecasting is designed for time series forecasting.

Linear learner is typically used for supervised regression or classification tasks.

AWS AI Study Guide References:

AWS unsupervised learning concepts

AWS clustering algorithms overview