Hi, Duaiekan—Interesting question! Only (B) works; (A) is ungrammatical. "Bring about" is a phrasal verb, as you are probably aware. Within the phrasal verb, "about" may be said to be an adverbial particle rather than a preposition.
Adverbial particles, even though they often look the same as prepositions, cannot be fronted in relative clauses or questions. This is one feature that shows that they are distinct from prepositions.
Incidentally, this is why Winston Churchill's famous statement about something being the sort of nonsense "up with which he will not put" is so funny. "Up" is an adverbial particle and cannot be fronted. "With which he will not put up" is fine.