Land, labor capital, and entrepreneurship are in an economic system
a. measurements of wealth
b. necessities for business
c. capital expenditures
d. factors of production

Land, Labor, Capital, and Entrepreneurs are considered to be the four factors of production. These four elements were categorised by economists in which these are in much significance in producing goods. In addition, if these inputs for production are maximised, it would yield a much greater economic profit.

He issued the emancipation proclamation. it started changing slavery, and eventually lead to the freedom of slaves.