(A) Primary
The work shown involves production through natural processes (such as farming, fishing, mining, or forestry), which belongs to the Primary sector.
The Primary sector includes all activities where goods are produced directly from natural resources — agriculture, fishing, mining, forestry, etc. Since the image depicts such a natural-process-based activity, option (A) is correct. Remember: Secondary = manufacturing; Tertiary = services; Quaternary = knowledge/research.