The Poseiq with the Caveat

A Major Poseiq made a sweeping caveat in his introduction

"My decisions are NOT meant to overturn existing customs"

Who said it?
A) Rema
B) Rosh
C) Bet Yosef
D) Tosafot
E) Rambam

Given this caveat which makes the most sense?

A) the poseiq was catering to concensus
B) given this caveat he was free to speak his mind freely w/o regard to hurting anyones feelings
C) This caveat was not meant as serious
D) none of the above

Shavua Tov
RRW