Correct answer choice is:
B. Cave-ins.
____________________________________________________________
Explanation:
Excavations and trenches are basically the man-made cuts inside the Earth's surface. These are made for multiple purposes such as mining or tunneling. One of the obvious risk while working in such excavations and trenches is cave-ins. It is basically collapse of that excavation or Trench. The roof of the mine collapses and people working under it get buried inside those excavations in trenches.
