Simple MVC NerdDinners Lambda

In this code from Microsoft's MVC Tutorial NerdDinners:

public class DinnerRepository {

private NerdDinnerDataContext db = new NerdDinnerDataContext();

//
// Query Methods

public IQueryable<Dinner> FindAllDinners() {
    return db.Dinners;
}

public IQueryable<Dinner> FindUpcomingDinners() {
    return from dinner in db.Dinners
           where dinner.EventDate > DateTime.Now
           orderby dinner.EventDate
           select dinner;
}

public Dinner GetDinner(int id) {
    return db.Dinners.SingleOrDefault(d => d.DinnerID == id);
}

//
// Insert/Delete Methods

public void Add(Dinner dinner) {
    db.Dinners.InsertOnSubmit(dinner);
}

public void Delete(Dinner dinner) {
    db.RSVPs.DeleteAllOnSubmit(dinner.RSVPs);
    db.Dinners.DeleteOnSubmit(dinner);
}

//
// Persistence 

public void Save() {
    db.SubmitChanges();
} 

}

What does:

public Dinner GetDinner(int id) {
    return db.Dinners.SingleOrDefault(d => d.DinnerID == id);
}

the "d" mean? How does this code work? I know it it bringing back dinners where dinnerid matches id from the function parameter. I don't understand the "d goes to..." means. I know it is a lambda but I don't really get it. What is the "d" for? What does it do?

Could this have been written without the lambda here (how)?

You should probably read up on anonymous methods.

Basically the code you are referring to can be written as an anonymous method without lamba syntax like this:

public Dinner GetDinner(int id) {    
   return db.Dinners.SingleOrDefault(delegate (Dinner d) {
                                       return d.DinnerID == id;
                                     });
}