[C II] luminosity-size relation of the CRISTAL sample. Symbols are based on the classification defined in Section 3.1. Each component of the pair/multiple-[C II] systems are shown separately. The right panel shows the histogram of [C II] sizes among categories with matched colors. We omit a histogram of multiple-[C II] because of the small sample size (N = 2). A histogram with a solid black line shows the size distribution of the entire CRISTAL sample. The [C II] sizes show the diversity at fixed [C II] luminosity, in which relatively compact sizes (R_e, [CII] ≲ 1 kpc) were challenging to be measured in the previous low-resolution data.