Which of these happened FIRST, following the assassination of Archduke Franz Ferdinand on June 28, 1914?

Responses
A France invaded Belgium.France invaded Belgium.
B Germany declared war on Russia.Germany declared war on Russia.
C Austria-Hungary declared war on Serbia.Austria-Hungary declared war on Serbia.
D Russia mobilized its forces for a possible war

1 answer

Following the assassination of Archduke Franz Ferdinand on June 28, 1914, the first significant event was:

C. Austria-Hungary declared war on Serbia.

Austria-Hungary declared war on Serbia on July 28, 1914, which set off a chain of events leading to World War I.