If You Can Score 26/26 On This One-Letter Quiz, Your Alphabet Skills Are Off The Charts

"K" is as close to official for 1000, in any context, as you can get and it's certainly used a lot when referring to sums of money, but at least in the US a "G'" or "grand" has been common street slang since before most people in the US had ever even heard of the Metric system. I can't speak for usage in other countries, so I don't how obvious it might be that "G" was the answer they were looking for. As for letters and wheels, aside from the answer being very obvious, in some fonts a lowercase o is extremely close to round of not perfectly round. Of course that's not to say the entire quiz isn't moderately stupid.

My first guess was "k" for $1000 as well. But I also have heard people say "grand". For shape of the tire, I think "o" is pretty clearly the right letter. None of these are what I'd call hard

I know it from gaming (early Playstation 2 era with that console release of the fighting game Tekken Tag Tournament to be exact), but I expect that it probably originally came from sports.

'take the loss' is a common expression.

I fixed your -1 in the charitable belief that perhaps the question should have said "opposite to E". That said, I don't think I've ever seen a compass that used the words instead of just the letters. A compass rose on a map frequently uses the whole word "North", but an actual compass?