Which implementation correctly splits a dataset into training and testing sets, stratifying by the target variable?
from sklearn.model_selection import train_test_splitX_train, X_test, y_train, y_test = train_test_split(X, y, stratify=True, random_state=42)
from sklearn.model_selection import train_test_splitX_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.3, random_state=42)
from sklearn.model_selection import train_test_splitX_train, X_test, y_train, y_test = train_test_split(X, y, stratify=X, random_state=42)
from sklearn.model_selection import train_test_splitX_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.3, stratify=y, random_state=42)