Which of the following best reflects a shield system?
a. A narrow excavation made below the surface of the ground.
b. A structure that is able to withstand the forces imposed on it by a cave-
in.
C. A series of horizontal levels or steps between vertical surfaces.
d. A system of structures that are inclined away from an excavation.
C, because a narrow structure evacuation below surface ground isn’t the best and a structure holding forces and isn’t to do with the question at all and d doesn’t matter if there include away or not
