Which constructor is correct for successfully extending the Dog class? class Dog { constructor(name) { this.name = name; } }; class Labrador extends Dog { // ... }

The choice provides a correct implementation of a constructor for the Labrador class that effectively extends the Dog class. By using the super(name) call, it invokes the constructor of the parent Dog class, allowing the Labrador class to inherit the properties defined there. This is crucial, as in JavaScript, when a class extends another class, it needs to call the parent class's constructor using the super keyword before attempting to set any properties of its own.

In this case, the Labrador class constructor accepts two parameters: name and size. The first step within the constructor is to call super(name), which initializes the name property in the Dog class. After that, the size property is set on the Labrador instance using this.size = size. This ensures that all required properties are correctly initialized when creating a new instance of Labrador.

The other options lack this necessary invocation of the parent class constructor or mismanage the parameters, resulting in incomplete or incorrect inheritance behavior. This highlights the importance of using super when extending classes in JavaScript to ensure proper initialization of inherited properties.