Visibility-plane stack of the [C I](1–0) data for ten sources from Chen et al. (2022), Frias Castillo et al. (2025). The uv-plane data were integrated over ±1 FWHM velocity range, radially binned with a step of 5 kλ. The exponential model with R_1/2 = 0.28 ± 0.10″ (2.2 ± 0.8 kpc, solid orange line) is marginally preferred by the evidence over the point-source one (dashed). We also show the best-fitting CO(1–0) profile (magenta) for comparison.