Who must hold a license issued by the department before installing fire extinguishers?

The correct choice is that an individual other than an apprentice must hold a license issued by the department before installing fire extinguishers. This regulation ensures that individuals who perform the installation are adequately trained and knowledgeable about safety standards, local codes, and best practices. An apprentice typically works under the supervision of a licensed individual and may not have the necessary expertise or training to perform installations independently. This requirement aims to protect public safety by ensuring that only qualified individuals are responsible for installing fire safety equipment.

In this context, the wording emphasizes the importance of licensing for those who are fully trained and not still undergoing training, which reinforces the standards that govern fire safety practices.