True statement about pelvic abscess is: (A) Uncommon cause of intra peritoneal abscess, (B) Associated with pyothorax, (C) May spontaneously drain via rectum, (D) Identified by CT if there is full bladder
Answer is C. Pelvic abscess :

It is common cause intraperitoneal abscess.
It is easily identified by CT if the bladder is empty.