Today this could be the greatest day of our lives
b) maybe not
c) may be
I'd like option C please and I'd like it now. I really hope Gary (Barlow) was right, because this was the first song that came on the radio today. I really hope I don't have to find Gary (Barlow) and have good chat with him about writing songs about hopes. Besides, he's about to start the biiiig Take That tour (for which I couldn't get a single ticket despite there are about 40 gigs), so I am sure he's busy (and this could be the greatest day of his life).
To sum this up: It's better for everyone if today could be the greatest day of our lives. Or, at least one of the greatest days.