I think "Is it 6 o'clock" is enough.
Yep, totally. Even "Is it six?" was on the list, but this was somehow overlooked O_o Thanks, now it's accepted!
I said,” It is now six o clock” and it marked it wrong - please fix
Hmm, we only accept "o'clock". I've never seen it being written "o clock" (maybe people do when they text to save time).