Explanation:

The correct answers are based on the Microsoft Azure AI Fundamentals (AI-900) Official Study Guide and the Microsoft Learn module "Explore fundamental principles of machine learning." In supervised machine learning, data is typically divided into three main subsets:
* Training set - used to train the model, i.e., to teach the algorithm the patterns and relationships between input features and output labels.
* Validation set - used to evaluate the model during training to tune hyperparameters and prevent overfitting.
* Test set - used after training to assess the final model's performance on unseen data.
Let's analyze each statement in light of these definitions:
* "A validation set includes the set of input examples that will be used to train a model." # NoThis is incorrect because the training set, not the validation set, contains the input examples used for model training. The validation set is separate from the training data to ensure unbiased evaluation.
* "A validation set can be used to determine how well a model predicts labels." # YesThis is correct. The validation set helps assess how effectively the model generalizes during training. It measures performance and helps tune model parameters for optimal results.
* "A validation set can be used to verify that all the training data was used to train the model." # NoThis is false. The validation set is not used to verify the completeness of training data usage. It exists independently to evaluate the model's performance during training cycles.
According to Microsoft Learn, using a validation set helps ensure that a model generalizes well and avoids overfitting to the training data. It plays a crucial role in refining and optimizing models before final testing.