Which of the following is something you can do to protect yourself from being pinned?

Which of the following is something you can do to protect yourself from being pinned? (1 point)

a. use wooden structures to support the sides of an excavation.
b. never stand between movingequipment or materials and an immovable structure, vehicle, or stacked materials.
c. work under suspended or raised loads or materials.
d. cut back the sides of a trench to a safe angle to prevent collapse?