E6C01:What is the function of hysteresis in a comparator?

Direct answer summary (2024-2028 NCVEC pool)

The official correct answer for E6C01 is To prevent input noise from causing unstable output signals.

The key fact is To prevent input noise from causing unstable output signals. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.