Fastest way to find common items across multiple lists in C#

Question

Given the following:

List> optionLists;

what would be a quick way to determine the subset of Option objects that a

Answer 1

I don't have the performance stats, but if you don't want to roll your own method, various collections libraries have a 'Set' or 'Set(T)' object that offer the usual set procedures. (listed in the order I would use them).

1. IESI Collections (literally just Set classes)
2. PowerCollections (not updated in a while)
3. C5 (never personally used)