Draw a veil over means to avoid discussing or hide something unpleasant. The correct answer is this meaning because the expression is used figuratively, not only by its literal words.

Examples:

• The family chose to draw a veil over the old dispute.
• In an HSC essay, Draw a veil over can express this meaning: to avoid discussing or hide something unpleasant.
• When this expression appears in a passage, connect Draw a veil over with the idea of to avoid discussing or hide something unpleasant.