Which stellar complex is associated with Rho Ophiuchi?

Rho Ophiuchi is associated with a dark nebula known as L1688, which is part of the larger Ophiuchus constellation. Dark nebulae are regions in space filled with dust and gas that can block the light from stars and other objects behind them, making them visible as dark patches against the lighter background of the Milky Way. The Rho Ophiuchi complex is particularly interesting because it contains not only the dark nebula but also young stars and protostars, indicating that star formation is actively occurring in this region. Other choices like planetary nebulae, star clusters, or open clusters do not accurately represent the nature of Rho Ophiuchi, as they involve different physical processes and structures that are not applicable in this case.