Answer:
A) make walls impassible
Explanation:
In unity, we can use a collier to make an impassible wall or other objects, for example, if we have a wall or floor of ice will be slippery, but this object won't be deformed, and we can add this collider in a ball, this object will have physic but this won't be deformed, the collider is invisible but the object is physic.
