Which of the following includes an example of plagirism?
a. In his essay about Marxism, John writes the following sentence: "The proletariat are laborers who live only so long as they find work, and find work only so long as their labor increases capital, which means that they are an exploited class.
b. Jean begins a research paper by saying "Taiwan is an island approximately one-hundred miles off the coast of China."
c. In an online discussion post Yuehan says: "In The Division of Labor in Society, Durkheim says that many modern problems can be attributed to anomie"
d. Juan submits a thesis including the sentence: "Putnam (1999) argues that civil society is closely related to democracy"