It's been a while. I'm very glad Chiyoyo's breaking out of her shell by leaps and bounds recently. First, she finally makes contact with Wataru, and now finally catches the attention of her class in a positive way.
What's the rational behind not grading a self-portrait and threatening to fail her instead? Is the artistic accomplishment any different?
And what kind of teacher doesn't realize someone has no partner during the entirety of the class and school year so far?
Wataru-kun finally gained some personality in this chapter, that's good.
@xtostos the meta answer is that the plot demands stakes. Arguably, maybe the art teacher recognized her hesitancy and was trying to push her out of her shell. I doubt one failing grade would've set her totally back (C's get degrees), but Chiyo is the type to spiral and avoid.