Which letter corresponds to the answer "M"?

The correct answer is "Mu." In the context of the Greek alphabet, "Mu" is the letter that corresponds to the designation "M." This is an essential concept in both Greek language studies and various fields such as mathematics and physics, where Greek letters are often used to represent variables or constants.

In contrast, "Nu" is the letter that corresponds to "N," "Omega" corresponds to "W" or "O," and "Alpha" represents "A." Hence, understanding the Greek alphabet's structure can help in identifying these letters accurately.