Remove duplicate data with LINQ

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
List ListItem = new List() { 'A', 'B', 'C', 'D', 'A', 'B', 'B', 'C' };
var uniqueItem = ListItem.Distinct().ToList();
}
}
}