Final answer:
Needle-less systems are an example of engineering control, which removes hazardous conditions or places a barrier between the worker and the hazard.
Step-by-step explanation:
Among the options provided, needle-less systems are an example of an engineering control. Engineering controls are strategies designed to protect workers by removing hazardous conditions or by placing a barrier between the worker and the hazard. This contrasts with administrative controls and personal protective equipment (PPE), which alter the way people work and protect them directly, respectively.
Other options such as wearing gloves, proper disposal of sharps, and handwashing are important safety measures but do not fall into the category of engineering controls. Rather, they are examples of personal protective equipment, proper waste management practices, and personal hygiene measures.