Consider the JavaFX code snippet given below. What must be added to the code to produce the scene? The line starts at (0,0) and ends at (100, 100). You may assume all required libraries are already imported. Also, you do not need to write the main method.

public void start (Stage primaryStage) { StackPane root = new StackPane (); /* add code here */ Scene scene = new Scene (root, 300, 250); primaryStage.setScene (scene); primaryStage.show(); }