how to call WCF method (generic)

[ServiceContract]
    public interface IService1
    {
       [OperationContract]
        FinalResult TotalMarks(List<result> lstQuestionsAndAnswers);

    }
public class FinalResult
   {
       [DataMember]
       public int Result { get; set; }
       [DataMember]

       public string MsgError { get; set; }
   }

 public FinalResult TotalMarks(List<result> lstQuestionsAndAnswers)
        {
            
            FinalResult objFinal = new FinalResult();
            
            try
            {
                
            
            }
            catch (Exception ex)
            {
             
            }
            finally { }
            return objFinal;
        }
    }

    public class Result
    {
        public string QuestionNo { get; set; }
        public string Answer { get; set; }
    }

//Client Side
  private void Form1_Load(object sender, EventArgs e)
        {
            ServiceReference1.Service1Client objService = new ServiceReference1.Service1Client();
            ServiceReference1.Result objResult = new ServiceReference1.Result();
        
            ServiceReference1.Result lst = new ServiceReference1.Result { };
            lst.QuestionNo = "Q1";
            lst.Answer = "B";

            objResult = null;
            objService.ChannelFactory.CreateChannel();
            //ServiceReference1.FinalResult=new ServiceReference1.FinalResult{}
            //objService.TotalMarks();
            
            //string Result = objService.TotalMarks();        
        }