Which of the following is evidence of a mixed economy?

A mixed economy is characterized by the coexistence of both private and public sector enterprises, and it often incorporates elements of both capitalism and socialism. The presence of social partnerships and regulations indicates collaboration between the government and the private sector, which is a hallmark of a mixed economy. In such a system, the government may intervene in certain areas to enhance social welfare, regulate industries, or provide public services while allowing market forces to operate in other sectors.

In contrast to this, having only privately owned businesses signals a purely capitalist economy. Strict government control without any private sector involvement would describe a command economy, while an economy based solely on barter depicts a situation where no currency exists, which is not reflective of a mixed economy's structure. Thus, the evidence of social partnerships and regulations highlights the underlying balance of government oversight and private enterprise that defines a mixed economy.