how does a landscape artist make an object in the foreground appear closer than an object in the background?

a. By making the object in the foreground, larger and comparison to the background objects.
b. By making the object in the foreground less detailed and comparison to the background objects.
c. By making the object in the foreground less colorful in comparison to background objects.
d. By making the object in the foreground, smaller and comparison to background objects.

a. By making the object in the foreground larger in comparison to the background objects.