Final answer:
The title unique to Japan and not found in Western Europe is C. Emperor which is a ceremonial position without governing power.
Step-by-step explanation:
The position/title that exists in Japan but not in Western Europe is C. Emperor. In Japan's parliamentary system, the emperor is a symbolic figure without governing power, where the title is unique to Japan and rooted in its history. the Prime Minister, currently the head of the government, is responsible for the real executive power.
Countries in Western Europe such as Germany have a Chancellor or a Prime Minister, and some have a President as the head of state, but the title of Emperor is not a present-day political position in Western Europe.