This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Mainlining is - 
Select and explain. 
A. Cocaine addiction, B. Homicidal cut wounds, C. Drug addicts using main veins for injecting drugs, D. Suicidal cut wounds
C: Drug addicts using main veins for injecting drugs
Answer: C: Drug addicts using main veins for injecting drugs 
Explanation: Most persistent drug abusers follow a classic progression from sniffing (similar to oral route) to skin popping (subcutaneous route), to mainlining (intravenous route) - each step bringing more intense experience, a higher addiction liability. With mainlining the initial 'thrill' is more intense.