Come full circle means to return to the original position or situation. The correct answer is this meaning because the expression is used figuratively, not only by its literal words.

Examples:

• After years abroad, his career came full circle.
• In an HSC essay, Come full circle can express this meaning: to return to the original position or situation.
• When this expression appears in a passage, connect Come full circle with the idea of to return to the original position or situation.