The correct answer is :
c. Forestry.
In forestry, a sawmill or lumber mill is used to get logs cut into lumber, producing timbers, usually for building purposes.
The eldest known mechanical mill is the Hierapolis sawmill, a Roman stone mill powered by water in Asia Minor dating back to the 3rd century AD.
The Industrial Revolution in the 18th century, brought the circular saw blade and the steam power in the 19th century, granting further mechanization. By the 20th century, electricity and high technology make most sawmills massive computerized.