What is the primary characteristic of a pyrotechnic device?

The primary characteristic of a pyrotechnic device is that it is designed to produce specific effects upon activation. This includes a wide range of planned reactions, such as the creation of visual displays, sounds, and other sensory effects that are intentionally designed for entertainment, display, or specific functions in various applications, including celebrations and theatrical productions. These devices often utilize explosive materials that require precise handling and control to ensure the intended outcome and safety.

Option A refers to visual displays, which while often a component of pyrotechnic devices, is not universally applicable, as some devices may focus on sound or other effects. Option B incorrectly implies that safety measures are unnecessary; all pyrotechnic devices require strict safety protocols to ensure the safety of operators and audiences. Option D incorrectly limits the pyrotechnic device to sound production only, disregarding the diverse effects that such devices can achieve. Thus, the correct answer emphasizes the intentional design and specific effects that are foundational to pyrotechnic devices.