E6D01:What is piezoelectricity?

Direct answer summary (2024-2028 NCVEC pool)

The official correct answer for E6D01 is A characteristic of materials that generate a voltage when stressed and that flex when a voltage is applied.

The key fact is A characteristic of materials that generate a voltage when stressed and that flex when a voltage is applied. Match that fact to the exact condition in the question; the other choices describe a different rule, band, component, or operating situation.