Which of the following correctly implements the default constructor of the Dog class?

Refer to the following class definitions:

public class Animal {
    private int age;
    public Animal() {
        age = 0;
    }
    public Animal(int a) {
        age = a;
    }
    // Other methods not shown
}

public class Dog extends Animal {
    private String breed;
    public Dog() {
        /* implementation not shown */
    }
    // Other methods not shown
}

Which of the following correctly implements the default constructor of the Dog class?

I super(1.0); breed = "Unknown";

II breed = "Unknown"; super();

III super(); breed = "Unknown";