Radio buttons offer choices in romaji, but the check only accepts kanji, thus correct answers are marked wrong.
Example: Survival Phrases #1 - Indispensable Words
Test:
How do you say "Thank you," in Japanese?
o Arigatou gozaimasu.
o Dō itashimashite.
o hai
o dōmo
Check:
How do you say "Thank you," in Japanese?
Your Answer: Arigatou gozaimasu.
Correct: 有り難うございます。