Now wait a second. Doesn't "tiu" mean "that" and you need "cxi tiu" (or "tiu cxi") to give it proximity and make it "this"?
In this video I talk about ĉi. The link should take you directly to the correct moment in the video.
You need the particle ĉi only if you want to discriminate this result and that result. We can assume that there is only one result, so tiu is enough.
I don't agree. If that is the case, they have to change it in the whole course. In other sentences "cxi" is mandatory. If you leave it out, the answer is wrong.
Not quite true. See video link elsewhere in the thread.