You are implementing an ASP.NET application. You add the following code segment.

public List GetNonSecretUsers()
{
string[] secretUsers = {"@secretUser", "@admin", "@root"}; List allpeople = GetAllPeople();
... }

You need to add code to return a list of all Person objects except those with a UserId that is contained in the secretUsers list. The resulting list must not contain duplicates. Which code segment should you use?

1. var secretPeople = (from p in allPeople
   from u in secretUsers
   where p.UserId == u
   select p).Distinct();
   return allPeople.Except(secretPeople);
   

2. return from p in allPeople
   from u in secretUsers
   where p.UserId != u
   select p;
   

3. return (from p in allPeople
   from u in secretUsers
   where p.UserId != u
   select p).Distinct();
   

4. List people = new List(
   from p in allPeople
   from u in secretUsers
   where p.UserId != u
   select p);
   return people.Distinct();