Validation of the CMD categories via the Monte Carlo method presented in Sect. 3.6. Top: Logarithmic distribution of the probability of CMD category parameter, P_CMD. The filled histogram represents the fiducial simulation (Sect. 3.5.1), while the open histogram represents the simulation that includes metallicity effects (Sect. 3.5.2). Bottom: CMD projection color-coded by the fiducial P_CMD values. Most of the stars have high P_CMD values, indicating that their assigned CMD categories are reliable. Targets with low P_CMD values are located near the boundaries of the CMD regions (see bottom panel of Figure 2), and their CMD categories are consequently less reliable.