To answer this question, you need to understand the concept of instance variables in object-oriented programming.
An instance variable is a variable that is declared within a class and is associated with individual instances (objects) of that class. Each instance of the class has its own copy of the instance variable, and changes made to the variable within one instance do not affect the variable in other instances.
However, the correct answer to this question is option A) 1. instance. This is because an instance variable is not shared by all instances of the class. Instead, it is unique to each instance. It is created and initialized when an object is created and exists as long as the object exists.
Option B) 2. abstract, option C) 3. interface, and option D) 4. static are incorrect answers for this question because they do not describe an instance variable. Abstract and interface are concepts related to defining the behavior of classes and cannot be used to declare variables. Static variables, on the other hand, are shared by all instances of a class, but they are not instance variables. Static variables belong to the class itself and are initialized once, regardless of the number of instances created.
Therefore, the correct answer is option A) 1. instance, as it correctly describes an instance variable that is unique to each object and exists even before the object is created.