【单选题】听力原文: Smoking is even more dangerous than previously believed, according to a major review of medical data by the World Health Organization's cancer agency. The International Agency for Research on Ca...
A.
They published scientific evidence to determine second hand smoke as a cause of cancer.
B.
They denied the suspicion that second hand smoke may cause cancer.
C.
They discovered all the causes of cancer.
D.
They agreed that moderate smoke won't cause cancer.