Answer:
Correct answer is chancellor.
Step-by-step explanation:
President is not a correct answer as in most of the countries president's authority is actually limited by the role of government.
Prime minister is also not correct, although in most European countries prime minister is at head of the government.
Chancellor is the correct answer as the chancellor's were at the head of German government even during the period of Empire. Today, at the head of German government is chancellor Angela Merkel.
Germany is a republic, so they don't have a monarch.