Final answer:
After the assassination of Archduke Ferdinand, Austria-Hungary gave Serbia 48 hours to accept the ultimatum.
Step-by-step explanation:
After the assassination of Archduke Ferdinand, Austria-Hungary gave Serbia 48 hours to accept the ultimatum. This ultimatum was a set of demands that Austria-Hungary presented to Serbia as a response to the assassination. It included items such as allowing Austro-Hungarian officials to conduct an investigation in Serbia and suppressing anti-Austrian propaganda.
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