问题如下：
Azarov asks Bector to develop ML models for unstructured stock sentiment datasets, Dataset ABC.
Bector notes that Dataset ABC is characterized by the absence of ground truth.
What percentage of Dataset ABC should be allocated to a training subset?
选项：
A. 0%
B. 20%
C. 60%
解释：
A is correct;
0% of the master dataset of Dataset ABC should be allocated to a training subset. Dataset ABC is characterized by the absence of ground truth (i.e., no known outcome or target variable) and is therefore an unsupervised ML model.
For unsupervised learning models, no splitting of the master dataset is needed, because of the absence of labeled training data.
Supervised ML datasets (with labeled training data) contain ground truth, the known outcome (target variable) of each observation in the dataset.
B is incorrect because 20% is the commonly recommended split for the crossvalidation set and test set in supervised training ML datasets.
C is incorrect because 60% is the commonly recommended split for the training set in supervised training ML datasets.
考点：Model Training - Method Selection
老师，ground truth不就是supervised吗？那不是应该6:2:2？为什么不选C？
