"Yes, that's right."
そうです means "that is so"/"that is right"
そうですよ implies that you're trying to convince or educate the listener. It is often translated like "It is like that, you know!"
そうですね asks for affirmation. It means "It is so, isn't it?" But it can also stand for contemplation, as in "Yeah, it is like that, isn't it. Hmm..."
It should be accepted. When I was in Okayama, it was super rare to ever hear anyone say "はい“。 It was always "そうですね" or just ”そうそう” So, at least based on what I heard, そうですshould be valid answers. That's what was said 99% of the time in places where you'd say "yes" in English. That's the problem with systems like this. Japanese and English are too different to make this sort of hardline decision on translations.
If you're doing it from English TO Japanese, it's not. I very rarely heard はい in conversation when I lived in Okayama. In places where you'd say "Yes" in English, it was much more common to say そうです or そうそう when I was in Okayama. I'm specifying Okayama because there's a lot of dialectical difference in Japanese. You can't take such a hardline blind idiot style of translation. The person who made this didn't understand... one of the two languages very well. Either the English or the Japanese, I'm not sure which one.