As part of the collectivization of agriculture launched in the soviet union, 3-5% of the "wealthiest" farmers, called were "liquidated"—selected for execution, removed to labor camps, or resettled on other land.
a. kulaks.
b. gulags.
c. zemstvos.
d. mirs.

The answer is Kulaks

Explanation:

The term Kulak referred to peasants who owned more than 8 acres of land and were considered “hesitating allies” of the revolution. In the 1930s, with Joseph Stalin in control of the Soviet Union, kulaks were decimated; peasants who became wealthier from 1906 to 1914 thanks to the Stolypin Reform were targeted as kulaks, but also anyone who withheld grain from the Bolsheviks. From 1929 to 1932 the dekulakization consisted on the arrest, deportation and execution of millions of prosperous peasants in order to seize their lands as part of Stalin’s first five years plan on the attempt to create new policies centred on a rapid industrialization and collectivization of agriculture (aimed to integrate individual landholdings and labour into collectively-controlled and state-controlled farms).