Answer:
Monocular cues.
Explanation:
As the exercise suggests, Corrine is impressed by cues that makes the painting look as it if had depth, which is known as monocular cues. This type of cues, as the exercise explains, are there to make the painting seem as if it had depth; the contrast between the monocular (using only one eye) and binocular (both eyes) is more obvious. So, in other words, what enables us to perceive the depth in the world around us is the use of monocular cues making it the thing Corrine is so impressed about in the painting.