Which is true about Mao Dun? ( )

A、Mao Dun did not take part in the May Fourth Movement in China.
B、Mao Dun did not help to establish the Chinese Communist Party in 1921.
C、(3) Mao Dun wrote for the party magazine The Communist Party.
D、(4) In 1949, he was Mao Zedong's secretary and President of the Writers’ Association until 1964.