The correct answer is Option 3: Vanguard.

M.N. Roy, also known as Manabendra Nath Roy, was an influential Indian revolutionary and political theorist who played a significant role in the Indian independence movement. He was associated with the Communist Party of India (CPI) and later became one of the founding members of the Communist Party of India (Marxist) [CPI(M)]. As an emigree Communist, he established several journals and publications to promote communist ideology.

Out of the given options:

Option 1: Kisan Sabha: Kisan Sabha, also known as the All India Kisan Sabha (AIKS), is a peasant organization that was founded in 1936. While M.N. Roy supported agrarian movements and peasant rights, he was not directly associated with the Kisan Sabha. Therefore, Option 1 is not the correct answer.

Option 2: The Worker: "The Worker" was an English-language communist weekly newspaper published in India during the early 1920s. However, M.N. Roy was not associated with "The Worker" journal. He played a prominent role in establishing the Communist Party of India and other communist organizations, but he did not publish or write for "The Worker." Therefore, Option 2 is not the correct answer.

Option 3: Vanguard: "Vanguard" was indeed an emigree Communist journal associated with M.N. Roy. It was founded by M.N. Roy in Berlin in 1920 and served as an important platform for disseminating communist ideas among Indian revolutionaries. Roy played a crucial role in publishing and editing "Vanguard," which became an influential publication within the Indian communist movement. Therefore, Option 3 is the correct answer.

Option 4: Anushilan: Anushilan was a secret revolutionary society in Bengal during the early 20th century, which aimed at achieving Indian independence through armed struggle against British colonial rule. While M.N. Roy was associated with revolutionary activities in Bengal, Anushilan was not a communist journal but rather a revolutionary organization. Therefore, Option 4 is not the correct answer.

In summary, the emigree Communist journal associated with M.N. Roy was "Vanguard," making Option 3 the correct answer.