According to the National Electric Code (NEC) article 800-179, which type of cable marking indicates that the cable is riser-rated?

The correct indication that a cable is riser-rated according to the National Electric Code (NEC) article 800-179 is the marking CMR. Riser-rated cables are specifically designed for vertical spaces between floors and must meet certain fire safety requirements to minimize the spread of fire between floors. The CMR rating signifies that the cable has passed the necessary tests to support this application.

The other markings serve different purposes: PLENUM indicates a cable that is suitable for use in air-handling spaces and necessitates a higher level of fire resistance than riser-rated cables. LSZH (Low Smoke Zero Halogen) cables are designed to emit minimal smoke and no halogen when exposed to fire, typically for environments that require stringent fire safety measures. NFPA refers to the National Fire Protection Association, which is an organization that develops codes and standards, rather than a specific rating for cable types. These distinctions clarify the specific applications and safety protocols that each cable rating is intended to address.