The correct answer is: A. Test set is used to test the accuracy of the hypotheses generated by the learner.
A test set is a set of data that is used to evaluate the performance of a machine learning model. The model is trained on a training set, and then the test set is used to see how well the model performs on data that it has not seen before. This helps to ensure that the model is not simply memorizing the training data, but is actually learning to generalize to new data.
Option B is incorrect because a test set is not used to discover the potentially predictive relationship. This is done using a training set. The training set is used to learn the relationship between the features and the target variable. The test set is then used to evaluate the performance of the model on new data.
Option C is incorrect because only option A is correct. Option B is incorrect, as explained above.
Option D is incorrect because option A is correct.