using System;

using System.Collections.Generic;

​

public class GeographyTest : List<string>{  

}

​

public class MathTest : List<string>{   

}

​

public interface IGenerator {

    GeographyTest GenerateGeographyTest();

    MathTest GenerateMathTest();

}

​

public class MiddleSchoolGenerator : IGenerator{

    public GeographyTest GenerateGeographyTest(){

        return new GeographyTest(){"Where can we find Grand Canyon?"};

    }

    public MathTest GenerateMathTest(){

        return new MathTest(){"800+20*5 = ?"};

    }

}

​

public class HighSchoolGenerator : IGenerator{

    public GeographyTest GenerateGeographyTest(){

        return new GeographyTest(){"Mata-Utu is the capital of which country or territory?"};

    }

    public MathTest GenerateMathTest(){

        return new MathTest(){"lg10*5^2 = ?"};

    }

}

​

public class School {

    private IGenerator generator;

    public School(IGenerator generator){

        this.generator = generator;

    }

    public GeographyTest GenerateGeographyTest(){

        return generator.GenerateGeographyTest();

    }

    public MathTest GenerateMathTest(){

        return generator.GenerateMathTest();

    } 

}

public class Program

{

    public static void Main()

    {

        var middleSchool = new School(new MiddleSchoolGenerator());

        Console.WriteLine(string.Join(",", middleSchool.GenerateMathTest()));

        var highSchool = new School(new HighSchoolGenerator());

        Console.WriteLine(string.Join(",", highSchool.GenerateMathTest()));

    }

}