Read the following statement carefully:
A . Smack is chemically diacetylmorphine which is a white , ordourless, bitter crystalline compounds.
B. Crack is a coca alkaloid , is obtained from coca plant Thebroma cocoa, and is usually snorted .
C. Smoking is associated with an increased risk of cancer of the lung .
D . The chronic use of drugs and alcohol damages the nervous system and liver.
Choose the correct statement only.