Concept:Public enterprises are business organisations owned and controlled by the government.
Explanation:The main source of finance for public enterprises is the government itself.
Funds are provided through direct grants, subsidies, and capital injections from the government treasury.
Shareholders and mortgage banks mainly finance private companies, not public enterprises.
Commercial banks may provide loans, but they are not the primary source of funding.
Therefore, government grants are the most important and largest source of finance for public enterprises.
Answer:C. government grants