The primary sector of the economy is concerned with activities that are directly dependent on the environment for the extraction and production of natural resources.
(A) Land: The fundamental natural resource for agriculture.
(B) Forest: Forestry and logging are primary sector activities.
(C) Mining: The extraction of minerals and ores from the earth is a classic primary sector activity.
All the options represent or are directly related to the extraction of natural resources and thus belong to the primary sector.