After four years: Ms Matrix Minutiae

The Ms ask:

1. Can you guess which M is described in each category?
2. For bonus points and eternal credit for EQ, can you guess which M volunteered the description?
3. Place your bets in the comments; answers posted next week! (Sample answer sheet provided below.)

Note: Every row is in a different order - no one is all "A," "B," or "C"... I know, I know, we're tough like that. Can anyone fill out the entire board?

(click for full-size!)