C. What is model validation, and why is it important?

1. It's the integration of the model into a production environment. It's important for real-time predictions.

2. It's the optimization of hyperparameters for the model. It's important for enhancing the model's performance.

3. It's the assessment of the model's performance using an appropriate evaluation metric. It's important to ensure the model effectively solves the identified business problem.

4. It ensures that the model not only fits the existing data but also likely generalizes to unseen data. It's important to prevent overfitting.