Which factor played a major role in china's economic growth since the late 1970s?

Economic reforms introducing market principles began in 1978 and were carried out in two stages. The first stage, in the late 1970s and early 1980s, involved the decollectivization of agriculture, the opening up of the country to foreign investment, and permission for entrepreneurs to start businesses.

the answer to your question is:

strong-mayor system

d. the right to establish a one-house legislature