A tong works on the principle of a lever, a rigid bar that pivots around a fulcrum to amplify force or motion.
Among the given options, window or door blinds are raised and lowered using a cord-and-pulley mechanism, which makes "pulley" the working principle behind blinds, in the same way "lever" is the working principle behind tongs.
Tweezers and nutcrackers also rely on lever-like action, and a see-saw is itself essentially a lever, so none of those match a pulley-based analogy as precisely as blinds do, making Blinds the correct answer.