What was the “black hand”?
a. an early organized crime outfit that was similar to the modern mafia
b. an early workers union that was a precursor to the fair labor association
c. an article that exposed unsanitary living in u. s. cities
d. a sculpture that represented working class struggles in the u. s.

The black hand was a secret serbian society that used terrorist methods to promote the liberation of Serbs outside Serbia from Habsburg or Ottoman rule and was instrumental in planning the assassination of the Austrian archduke Franz Ferdinand, precipitating the outbreak of World War 1.

So based on that I believe the answer is, A.