In 1914, Archduke Franz Ferdinand of Austria and his wife Sophie are shot to death by a Bosnian Serb nationalist during an official visit to the Bosnian capital of Sarajevo. The killings sparked a chain of events that led to the outbreak of World War I by early August.
Source: www.history.com
Answer:
We would need the whole question or page even to solve this, my best shot would be 24 because 15+9= 24. If this is wrong please forgive me.
Crust:outer silicate solid crust
mantle:highly viscous
core:solid inner core
