Suppose Animal is an interface that specifies a single method – speak. Now suppose the Dog class implements the Animal interface. In addition to the speak method, the Dog class also has a method called wagTail. Now consider the following code.
Animal a = new Dog();
a. wagTail();

"This above code gives the compile time error".

Explanation:

Missing information:

The question does not include the "what is the output" line.

Detailed Explantion:

The above question holds a class dog that implements an interface. But the code "Animal a = new Dog();" wants to make an object of the Animal interface, which is not possible.It is because the interface and the abstract class definition say that no user can create a direct object of the interface or the abstract class.If any user wants to call the interface method to speak in the above scenario, then he needs to make the object of Dog class like "Dog a=new Dog()", then an object can call the method of the interface.So the above code gives the compile-time error.