What kind of button to use?
[ETA: That's not a button in the picture; it's a row counter. I just put it there to show where the buttonhole is.]

This is a hurry-up gift for our pal Phoenix. The Things will be going to her bday party on Saturday, and Michele says Phoenix’s fave color these days is light green. I was hoping to make a more normal scarf, but, well, I ran out of all the yarn ‘cept the variegated one. So, what kind of button should I use???
Yarn: Lucci Yarns Style 2019 loop wool (color: Turner’s Palette), more than half the ball left + 1 strand light green petro (ran out second) + 1 strand lighter green petro (ran out first).
Needles: US 13’s
This is SOOOO soft!