 Complete the following phrase:  Following the death of Mao in September 1976 and the coup détat against the radical Gang of Four a month later, Chen became increasingly active in the countrys political life. He and General Wang Zhen petitioned Party chairman Hua Guofeng to rehabilitate Deng Xiaoping at the March 1977 CPC CC Work Conference, but were turned down. After Deng was rehabilitated later that year, Chen led the attack on the Maoist era at the NovemberDecember 1978 CPC CC Work Conference, raising the sensitive six issues: the purges of Bo Yibo, Tao Zhu, Wang Heshou and Peng Dehuai; the 1976 