Quiz Yourself: Interfaces

Consider the code below where ISerializable inherits from two other interfaces. How many total interfaces must MyClass satisfy to compile successfully?

public interface IDisposable { void Dispose(); }
public interface ICloneable { object Clone(); }
public interface ISerializable : IDisposable, ICloneable { void Serialize(); }

public class MyClass : ISerializable 
{ 
    // Implementation details...
}