The hashCode method is defined in the Object class in Java. Therefore, the correct answer is: a) Object
In Java, the Object class is the root class for all classes. It is at the top of the class hierarchy. Every class in Java is either directly or indirectly a subclass of the Object class. The Object class defines several methods that are common to all objects, and one of them is the hashCode method.
The hashCode method in the Object class is used to generate a hash code for an object. This hash code is an integer value that is typically used in hash-based data structures like hash tables. The purpose of the hashCode method is to provide a numeric representation of the object's contents in a way that is likely to be unique for different objects.