The optimal lighting type to support color closed-circuit television (CCTV) system effectiveness is metal halide. Metal halide lighting provides a high color rendering index (CRI), which means it renders colors more accurately and naturally compared to other lighting options. This makes it particularly effective for color CCTV systems, as accurate color representation is crucial for identifying objects and individuals. Other options like mercury vapor, low-pressure sodium vapor, and high-pressure sodium vapor have lower CRI values and are not as effective for color-based surveillance systems.