Logic devices with 0, 1, and high-impedance output states✓Correct answer
Logic devices that utilize ternary math
Logic with three output impedances which can be selected to better match the load impedance
A counter with eight states
Explanation
Tri-state logic adds a high-impedance state to the usual logic 0 and logic 1, so a device can electrically remove itself from a shared bus and let another device drive it. It has nothing to do with ternary arithmetic, with selecting output impedances to match a load, or with the number of states in a counter.