Translation:I waited for them for an hour today.
"Today I waited for them for one hour" or "I waited for them for one hour today" should also be acceptable.
Like I've already said elsewhere, there are a LOT of mistakes in the answer bank for this particular module. You good people will probably want to give priority to fixing this one first.
No, its "an hour". This is because the "h" is silent so when spoken "hour" begins with a vowel sound.
You used the wrong word. I waited for them for an hour today
What's wrong with "I waited for them an hour today"