Austria issued serbia a ten-part ultimatum in response to
a. serbia’s alliance with russia.
b. serbia’s violation of italy’s neutrality.
c. the role of serbian and slavic nationalists in the assassination of the austrian archduke.
d. serbia’s declaration of war on austria.

It's 1914. Serbia, a part of Austria at the time, had begun to want independance. When Austrian duke Franz Ferdinand visited Serbian capital that year, he was assassinated.
Austria wanted to start a war, but wanted to look peaceful to other European powers, as if they had given the Serbians a chance to avoid the war they were trying to start. So the Austrians issued Serbia an ultimatum.
No sane ruler could accept this ultimatum. It would have allowed Austrians to conduct random searches in Serbia, violating their freedoms. It was war.
c. the role of Serbian and Slavic nationalists in the assassination of the Austrian Archduke.

The events leading up to WW1 are really interesting--check out Extra History if you want to learn more about it

 C. The role of Serbian and Slavic nationalists in the assassination of the Austrian Archduke.

The ultimatum came after Franz Ferdinand, the archduke of Austria, was assassinated along with his wife in Serbia.  On July 23, 1914 (about a month after the assassination), the government of Austria-Hungary issued an ultimatum to Serbia.  Briefly, the ultimatum demanded that Serbia would ...

allow Austria-Hungary to conduct an investigation into the assassination;stop all anti-Austrian propaganda being circulated in Serbia;eliminate all terrorist groups such as the Black Hand, which was the group believed to be responsible for the archduke's assassination.

The government of Austria-Hungary demanded an answer from Serbia's government within 48 hours, or war would happen.  And war did happen -- a conflict that ended up involving many other countries, which we now call World War I.

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