"What a bunch of bull!” (3)
I believe the answer is:
bah
(Other definitions for bah that I've seen before include "Exclamation of disgust or annoyance" , "Expression of disgust or contempt" , "Comic expression of contempt" , "Exclamation of contempt or disgust - Scrooge used to say it" , "''...! Humbug!'' (Scrooge)" .)