C# Online Compiler | .NET Fiddle

using System;
using System.Linq;
using System.Collections.Generic;

public class Program
{
	public static void Main()
	{
		IList<Student> studentList = new List<Student>() 
		{ 
			new Student() { StudentID = 1, StudentName = "John", Age = 18, StandardID = 1 } ,
			new Student() { StudentID = 2, StudentName = "Steve",  Age = 21, StandardID = 1 } ,
			new Student() { StudentID = 3, StudentName = "Bill",  Age = 18, StandardID = 2 } ,
			new Student() { StudentID = 4, StudentName = "Ram" , Age = 20, StandardID = 2 } ,
			new Student() { StudentID = 5, StudentName = "Ron" , Age = 21 } 
		};

		IList<Standard> standardList = new List<Standard>() 
		{ 
			new Standard(){ StandardID = 1, StandardName="Standard 1"},
			new Standard(){ StandardID = 2, StandardName="Standard 2"},
			new Standard(){ StandardID = 3, StandardName="Standard 3"}
		};
		var teenStudentsName = from s in studentList
                       where s.Age > 12 && s.Age < 20
                       select new { StudentName = s.StudentName };

		teenStudentsName.ToList().ForEach(s => Console.WriteLine(s.StudentName));
	}
}

public class Student
{ 
    public int StudentID { get; set; }
    public string StudentName { get; set; }
    public int Age { get; set; }
    public int StandardID { get; set; }
}

public class Standard
{ 
    public int StandardID { get; set; }
    public string StandardName { get; set; }
}

 
using System;
using System.Linq;
using System.Collections.Generic;
​
public class Program
{
    public static void Main()
    {
        IList<Student> studentList = new List<Student>() 
        { 
            new Student() { StudentID = 1, StudentName = "John", Age = 18, StandardID = 1 } ,
            new Student() { StudentID = 2, StudentName = "Steve",  Age = 21, StandardID = 1 } ,
            new Student() { StudentID = 3, StudentName = "Bill",  Age = 18, StandardID = 2 } ,
            new Student() { StudentID = 4, StudentName = "Ram" , Age = 20, StandardID = 2 } ,
            new Student() { StudentID = 5, StudentName = "Ron" , Age = 21 } 
        };
​
        IList<Standard> standardList = new List<Standard>() 
        { 
            new Standard(){ StandardID = 1, StandardName="Standard 1"},
            new Standard(){ StandardID = 2, StandardName="Standard 2"},
            new Standard(){ StandardID = 3, StandardName="Standard 3"}
        };
        var teenStudentsName = from s in studentList