The original author's "I just pause there" answer for the stanza division sounds like a classic example of the author subconsciously building in structural features, or just forgetting why she structured it that way in the first place because she associates it with performances rather than a process of writing now. (It's not as if programmers necessarily remember why every little structural feature of programs they wrote some time ago are still there, after all)

Having Googled the original poem, there's really only one place you could split it into two stanzas, which coincides with repetition of phrases from the first stanza - the only repetition in the poem - and which is where the poem switches from thinking about Monday to it being Sunday at midnight. I don't think the author put the pause there purely to save her breath...

(you can read the original poem - typeset without the stanzas - and the original questionable high school questions here http://www.jiskha.com/display.cgi?id=1394137792)

It's also worth noting that even if the assumed authorial intent is completely wrong (like many other theories of authorial intent attributed to authors who usually aren't around to question it), it's a far more reasonable interpretation than the other multiple choice answers. Though this doesn't really apply to some of the other examples