I would bet on Abraham because he is the legitimate alpha male of the group and Negan did not like how he looked at him.
Now the most logical thing IN REAL LIFE would be to kill Rick for the group to lose complete hope BUT killing the leader will let an open door for a stronger one (Abraham) to take over.
and Negan needs Eugene for the bullets. But as Eugene gave to Rick the paper with the "how to fabric bullets for dummies" it was maybe a "hint" for us to guess who is going to die -now Eugene is useless since anyone can make bullets-
And even if i like Glenn, I wouldn't mind him to go because his death is the reason Maggie became the leader of a new group in another community (comics)
Not sorry for the spoilers