Abstraction c#, C#

Language: Layout:

//Title of this code
//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;

namespace Rextester
{
    public class Program
    {

public static void Main(string[] args)
        {
            /*BaseEmployee Object can not be created since this is declared as Abstract
            Following LOCs will return compilation error if uncommented.*/
            //BaseEmployee baseEmployee = new BaseEmployee();
            //baseEmployee.EmployeeID = "EMP001";
            //baseEmployee.EmployeeAddress = "3400 Lee Highway, VA 22031";
            //baseEmployee.EmployeeName = "John Doe";
            //Base Employee Calculate Salary can be called that shouldn't be accessible
            //var baseSalary = baseEmployee.CalculateSalary(34);
            //SalesExecutive and Manager objects are successfully created.
            Car Dc = new driver();
            Dc.details();           
            
            
            Mechanic m= new Mechanic();      
         
            Console.WriteLine("Formula is:"+m.DisplayMakeFormula());
            
           
        }
    }
    public abstract class Car
    {
        public string modelname { get; set; }
        public string color { get; set; }                
        public abstract void  details();
        
    }
   
    public class driver : Car
    {
       
        public override void details()
        {
            modelname = "innova";
            Console.WriteLine("Car model name:"+modelname);
            color = "white";
            Console.WriteLine("Car color:"+color);
            
        }
      
    }

public class Mechanic: Car
    {
        private string formula = "a*b";
        private string GetEngineMakeFormula()
        {
            return formula;
        }
        public string DisplayMakeFormula()
        {
            
            //"GetEngineMakeFormula()" is private but accessible and limited to this class only
            return GetEngineMakeFormula();
        }
        public override void details()
        {
            modelname = "innova";
            Console.WriteLine("Car model name:"+modelname);
            color = "white";
            Console.WriteLine("Car color:"+color);
            
        }
      
    }
    
}

Show compiler warnings [ + ] Show input
Compilation time: 0.06 sec, absolute running time: 0.08 sec, cpu time: 0.06 sec, average memory usage: 16 Mb, average nr of threads: 4