Analyze the following code:

```
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;

public class Test {
public static void main(String[] args) {
DoubleProperty balance = new SimpleDoubleProperty();
balance.addListener(ov ->
System.out.println(2 + balance.doubleValue()));

balance.set(4.5);
}
}
```
a. The program displays 4.5.
b. The program displays 6.5.
c. The program would display 4.5 if the balance.set(4.5) is placed before the balance.addLisnter(...) statement.
d. The program would display 6.5 if the balance.set(4.5) is placed before the balance.addLisnter(...) statement.

b. The program displays 6.5.