A cut-throat competition means very severe competition in which people may act ruthlessly. The correct answer is this meaning because the expression is used figuratively, not only by its literal words.

Examples:

• Admission to the top college became a cut-throat competition.
• In an HSC essay, A cut-throat competition can express this meaning: very severe competition in which people may act ruthlessly.
• When this expression appears in a passage, connect A cut-throat competition with the idea of very severe competition in which people may act ruthlessly.