Context: European Travel Commission divides the European region on the basis of Tourism Decision Metrics (TDM) model. Countries which belong to the Southern/Mediterranean Europe are:

Question: What does TDM stand for?
Answer: Tourism Decision Metrics

Question: Which group uses TDM as a metric?
Answer: European Travel Commission

Question: Which group uses European regions as a metric?
Answer: Unanswerable

Question: Who divides the mountainous regions?
Answer: Unanswerable

Question: What model shows countries grouped by population?
Answer: Unanswerable

Question: What region does Ireland belong to? 
Answer: Unanswerable

Question: Who divides the Asian region?
Answer: Unanswerable