HOTSPOT
You are developing the following classes named:
Class1
Class2
Class3
All of the classes will be part of a single assembly named Assembly.dll. Assembly.dll will be used by
multiple applications.
All of the classes will implement the following interface, which is also part ofAssembly.dll:
public interface Interface1
{
void Method1(decimal amount);
void Method2(decimal amount);
}
You need to ensure that the Method2 method for the Class3 class can be executed only when
instances of the class are accessed through the Interface1 interface. The solution must ensure that
calls to the Method1 method can be made either through the interface or through an instance of the
class.
Which signature should you use for each method? (To answer, select the appropriate signature for
each method in the answer area.)
Answer: 
3,4
if a class implements an interface explicitly, the program cannot acccess the interfaces members through a class instance. it must use an instance of the interface.
e.g public class teacher: Istudent{List Istudent.Courses{….
you need to convert the class instance into an interface instance to access the method
if class implements an interface implicitly the program can access the interface members threough a class instance of interface instance.