  Experimental measurements in pA collisions indicate no D meson suppression
($R_{\rm pPb} \sim 1$) but a surprisingly large $v_2$. To better understand
these results we propose a system size scan at the LHC involving $^{16}$OO,
$^{40}$ArAr, $^{129}$XeXe and $^{208}$PbPb collisions. Using Trento+
v-USPhydro+DAB-MOD to make predictions, we find that the $R_{\rm AA}$ tends
towards unity when the system size is decreased, but nonetheless, in the most
central collisions $v_2\{2\}$ is almost independent of the colliding system.
These results are analyzed in light of path length and initial eccentricity
variations.
