Linq Queries with optional parameters

So i'm doing some work with Telerik OpenAccess and I had the task to write a query that has 6 parameters and the need for any combination of those parameters to be the criteria.

So here's what I did

IQueryable personQuery;

personQuery = from obj in ObjectScope.Extent()
select obj;

if (firstName != null)
personQuery = personQuery.Where(person => person.FirstName == firstName);

if (lastName != null)
personQuery = personQuery.Where(person => person.LastName == lastName);

if (middleName != null)
personQuery = personQuery.Where(person => person.MiddleName == middleName);

if (ssn != null)
personQuery = personQuery.Where(person => person.SSN == ssn);

if (city != null)
personQuery = personQuery.Where(person => person.CurrentAddress.City == city);

IList personList = personQuery.ToList();

This is the easy way to do it. I'll show you more advanced ways later.