At loose ends means having nothing useful to do or feeling unsettled. The correct answer is this meaning because the expression is used figuratively, not only by its literal words.

Examples:

• After the exams, many students felt at loose ends.
• In an HSC essay, At loose ends can express this meaning: having nothing useful to do or feeling unsettled.
• When this expression appears in a passage, connect At loose ends with the idea of having nothing useful to do or feeling unsettled.