"How are you?"
Yes, ʻoe should be an option, but it was not present. The accepted choice is "kāua," but I find kāua does not match the sentence question. Kāua is listed as "we" dual-inclusive in the online dictionaries, see wehewehe.org. Dual-inclusive meaning "you and I. " I think the question should have been - How are "you and I" for kāua to be the correct answer. Or the question to How are "we" for kāua as an answer, since kāua is accepted as "we" in other questions.
If the language code reviewers have a clear answer for their choice of Kāua as an answer for "How are you?" please share that information.
Interesting challenge to figure out what the software will accept as an answer.
Maybe it expects you to use an ʻokina instead of an apostrophe/single quote? According to the Klingon Duolingo moderators, since Duolingo removes all punctuation and capitalization from your answer before analysing it, apostrophes at the beginning and end of the word aren't parsed by it.