Kyouryuu-chan to Kaseki-kun - Vol. 1 Ch. 9 - The Mysterious Return Home

[Weebman0]

Almost certainly that or professor considering what comes in the next chapter, but I hadn't read that yet. Whoops.

Problem is it's really vague so in the moment you're supposed to wonder what specifically she means about how they came to be, and giving a concrete profession takes some of that away.

You could always leave it as sensei and put in a tl note. I'm pretty sure most people reading manga know what a sensei refers to anyway.