Which phrase from the paragraph best the reader understand the meaning of the underlined phrase?

i decided to have a sleepover and asked my closest friends. then i decided to invite the new girl, dawn, who had just moved in a few doors down. little did i know that i would open a can of worms. i had no idea that my friend jenn had already met dawn and that the two girls totally disliked each other. if i had known i was going to create such a problem, i never would have had the sleepover.

a.
little did i know

b.
never would have had

c.
had no idea

d.
create such a problem