Which code fragment is illegal?
A.
class Base1 {
abstract class Abs1 { }}
B.
abstract class Abs1 {
void doit () { }
}
C.
class Basel {
abstract class Abs1 extends Basel {
D.
abstract int var1 = 89;
Explanation:
The abstract keyword cannot be used to declare an int variable.
The abstract keyword is used to declare a class or method to be abstract[3]. An abstract method has
no implementation; all classes containing abstract methods must themselves be abstract, although
not all abstract classes have abstract methods.