Analyze the following code.

```
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.stage.Stage;

public class Test extends Application {
@Override // Override the start method in the Application class
public void start(Stage primaryStage) {
// Create a button and place it in the scene
Button btOK = new Button("OK");
btOK.setOnAction(e -> System.out.println("OK 1"));
btOK.setOnAction(e -> System.out.println("OK 2"));

Scene scene = new Scene(btOK, 200, 250);
primaryStage.setTitle("MyJavaFX"); // Set the stage title
primaryStage.setScene(scene); // Place the scene in the stage
primaryStage.show(); // Display the stage
}

/**
* The main method is only needed for the IDE with limited JavaFX
* support. Not needed for running from the command line.
*/
public static void main(String[] args) {
launch(args);
}
}```
a. When clicking the button, the program displays OK1 OK2.
b. When clicking the button, the program displays OK1.
c. When clicking the button, the program displays OK2.
d. The program has a compile error, because the setOnAction method is invoked twice.

c