Answer:
The correct answer is: tin mining operations.
Step-by-step explanation:
Nok Art refers to large human or animal heads, body parts and figures made of terracotta pottery, which was found in Nigeria. It represents the earliest sculptural art in West Africa. It was accidentally discovered in 1928, deep in the alluvial deposits of tin mining sites during the archaeological excavations.
These figures are distinguishable by their large heads and expressed facial features and it depicts important people and ancestors.