Radial acceleration relation of ten undisturbed galaxy clusters. Black points show the results with both measured dynamical and baryonic masses, while grey points show the radii where there are only measured dynamical masses. The gas masses at these radii are derived from extrapolations based on the surface brightness fits. The dotted line is the line of unity, and the red line is the RAR established with late-type galaxies (McGaugh et al. 2016; Lelli et al. 2017b). Light gray points represent the SPARC galaxies from McGaugh et al. (2016). The total accelerations overshoot the RAR in galaxies, suggesting a missing baryon problem in the inner regions of galaxy clusters for MOND Milgrom (1983).