Read the excerpt below and answer the question.

Still further to a satisfactory arrangement, I procured a high green folding screen, which might entirely isolate Bartleby from my sight, though not remove him from my voice.

What does the folding green screen represent in this excerpt from Melville’s "Bartleby the Scrivener"?

the narrator’s loathing of Bartleby’s existence
the figurative wall that existed between them all along
the narrator’s deficient understanding of human nature
the distrust that remained between Bartleby and the narrator