B: A class can be declared as public or private.
C: You can declare two kinds of classes: top-level classes and inner classes.
You define an inner class within a top-level class. Depending on how it is defined, an inner
class can be one of the following four types: Anonymous, Local, Member and Nested top-level. A nested top-level class is a member classes with a static modifier. A nested top-level class is just like any other top-level class except that it is declared within another class or interface. Nested top-level classes are typically used as a convenient way to group related classes without creating a new package. The following is an example:
public class Main { static class Killer {