This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Substance Related and Addictive Disorders, Subject name: Psychiatry
Male staed drinking alcohol at age of 20 years, presently taking 3 quaers daily over 30 years, complains that now he gets the kick in 1 quaer. Probable diagnosis is: 
Select and explain. 
A. Tolerance, B. Mellanby phenomenon, C. Reverse tolerance, D. Cross tolerance
C: Reverse tolerance
Answer: C: Reverse tolerance 
Explanation: Reverse tolerance refers to the phenomenon where the intoxicating effects of alcohol are seen progressively with lower dosages. Tolerance is the need or increased amounts of the substance to achieve the same positive psychological effect. Cross-tolerance is the development of tolerance to one substance as the result of using another substance. Mellanby effect- Intoxicating effects at a paicular BAC