Productive inputs that are actually or virtually fixed in supply are known as

A) renewable natural resources.
B) natural capital.
C) nonrenewable natural resources.
D) alternative fuels.

Nonrenewable Natural Resources

Natural resources, such as oil or coal, that cannot be replenished within a human lifetime, leading to depletion with use.

Natural Capital

The world's stock of natural resources, which includes geology, soils, air, water, and all living organisms, providing ecosystem services that benefit humans.

Alternative Fuels

Fuels other than traditional sources (like petroleum oils) used for transportation, including electric, hydrogen, biofuels, and natural gas, to reduce pollution and dependency on oil.