prevented Lead from creating Opportunity and Account while qualify lead to opportunity

prevented Lead from creating Opportunity and Account

 public void Execute(IServiceProvider serviceProvider)

{

  IPluginExecutionContext contextPlugin = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));

  IOrganizationServiceFactory factory = (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));

  IOrganizationService service = factory.CreateOrganizationService(contextPlugin.UserId);

    if (contextPlugin.MessageName != "QualifyLead") return;

        OptionSetValue LeadStatecode = new OptionSetValue();

        OptionSetValue LeadStatuscode = new OptionSetValue();

        EntityReference LeadRef = null;

        try

        {

         LeadRef = (EntityReference)contextPlugin.InputParameters["LeadId"];

         Entity Lead = service.Retrieve("lead", LeadRef.Id, new ColumnSet(true));

         if (LeadRef.LogicalName != "lead") 

         { return; }

            LeadStatecode = Lead.GetAttributeValue<OptionSetValue>("statecode");

            LeadStatuscode = Lead.GetAttributeValue<OptionSetValue>("statuscode");

            if (LeadStatecode.Value == 0 && LeadStatuscode.Value == 1)

            {

                contextPlugin.InputParameters["CreateOpportunity"] = false; // set to true by default 

                contextPlugin.InputParameters["CreateAccount"] = false;   // set to true by default 

            }

         }

        catch (InvalidPluginExecutionException ex)

        {throw new InvalidPluginExecutionException(ex.Message);}

        catch (Exception ex)

        {throw new InvalidPluginExecutionException(ex.Message);}

}