Answer: featuresCol

The `featuresCol` parameter in a LinearRegression model is crucial as it specifies the column containing the independent variables (features) the model will learn from. Here's why the other options are incorrect: - `labelCol`: Identifies the column with the target variable to predict, not the features. - `inputCols`: Typically not used in LinearRegression; more common in algorithms requiring multiple input columns. - `outputCol`: Defines the column name for the model's predictions in the output DataFrame, not the features column. Understanding these parameters helps in correctly configuring the model for training and prediction.

Author: LeetQuiz Editorial Team