These comments helped, notedly the one which point out seeing a comparison is key even if it doesn't align exactly as the lesson shows. The instructor pointed out the john and kate example which I translated as such:

Some cultivars of corn relationship to sorghum.

Some cultivars of corn relationship with most other cultivars of corn.

So it'd be sorghum vs. most other cultivars of corn because Some Cultivars is the constant here when comparing the two. They are NOT being compared against each other, but are being compared on how they each relate to Some Cultivars.

Even with my explaining its still hard to see it that way, I want to resort back to Some cultivars vs. Most other cultivars and which is closer to sorghum. But I can force myself to think that logically it all i can answer for sure with the information given is that Some Cultivars are closer. There's no info stated about the closeness to anything else.