Clauda's back! She had a semi$-$relaxing spring break $($even though she still had to go to work so it wasn't a "REAL" break$)$ but if she ever has to look at another Cost of Production Report, she swears she will punch somebody in the face!

She thought she'd like chapter $21($learning about cost behavior$)$ much better than chapter $20.$ That was, at least, until she saw the "Varlable cost graphs" in Exhibit $1($page $1023)$ and the "Fixed cost graphs" in Exhibit $3$ on page $1025.($She hasn't yet seen the mixed costs on page $1026!)$

"What do we need those for?" she mutters under her breath. She thinks she understands the first graph on page $1023$ and the first graph on page $1025$ but she thinks the authors made a mistake with the second grophs in those sets. "Typical old$-$men$-$accountants," she says to herself, "doing things the stupid way and messing up just to confuse us:$"$

Please explain to Claudia what each of those four graphs means and whether the textbook authors made mistakes, as she claims, with the unit$-$cost graphs. Why are the unit$-$cost graphs so different from the total cost graphs?