When it's time for a new monarch, what is the most common way that the next
monarch is chosen?

An elective monarchy is a monarchy ruled by an elected monarch, in contrast to a hereditary monarchy in which the office is automatically passed down as a family inheritance. The manner of election, the nature of candidate qualifications, and the electors vary from case to case

Explanation:

An elective government is a government administered by a chosen ruler, rather than an innate government wherein the workplace is naturally passed down as a family legacy. The way of political race, the idea of applicant capabilities, and the balloters change from case to case

*automatically passed down as a family inheritance*

"germany's geographic location was an advantage when it was on the offensive in the war because it was situated next to an extremely wide river, the rhine, which was difficult for the allies to cross."