Louie G’s Tuesday Morning Trivia Question

New research found that Tuesday is the most depressing day of the week. I always thought that Monday was the most unhappiest day.Another study found that taking Louie G's Tuesday Morning Trivia quiz is the best way to combat unhappy Tuesdays.

Today's question is about the Greek  Alphabet. On a side note, I am a big fan of sororities.

Anyways, here is today's Trivia Question:

What is the last letter of the Greek Alphabet?