?: Hook-Theory 3.6 ...brick wall

Thus far I’ve aced all the questions.
but this one stopped me in my tracks.

This tells me I don’t understand this concept.
I know what stable scale degrees are
(scale degrees that a sounding chord entails)
I know what unstable scale degrees are
(not that)
I know what strong and weak beats are
I know what resolution is
I aced all of the questions in all of the other sections up to this point.

I can even list out the scale degrees of each chord
(i did that on paper to try and figure out the question)
I 1, 3, 5
ii 2, 4, 6
iii 3, 5, 7
IV 4, 6, 1
V 5, 7, 2
vi 6, 1, 3
vii 7, 2, 4

But yeah…
Even when I gave-up and read the answer…

Something isn’t connecting in my head here.

is there a way to drill this?
level up my understanding?
(I am sub-scribed to chord crush. is there perhaps something in there that can help me?)

The example shows a single bar playing the scale degrees 7 and 1. The 7 is played on the first strong beat and the 1 is played on beats 2 (weak), 3 (strong), and 4 (weak). You listed out the scale degrees of the chords, so you can see which chords contain the scale degrees 7 or 1. You should be able to see in your list of chords that no basic chord contains both scale degrees 1 and 7. This means that one of those notes will have to be an unstable scale degree.

If you understand that an unstable scale degree played on a strong beat should be followed by a stable scale degree to resolve the tension, then you might notice that the most important scale degree for determining the suitable chords for this bar is the first scale degree.

The chords I, IV, and vi all have the first scale degree in it, which allows it to be a stable scale degree.

If you try and choose chords to make scale degree 7 stable, the note on beat 3 becomes unstable and does not resolve on beat 4.