Top: continuum images of the HD 135344B, HD 169142, and HD 97048 disks highlighting the locations of candidate giant exoplanets and the C/O of the disk gas at the approximate orbital location of these planets. Bottom: a compilation of C/O ratios measured for directly imaged exoplanets around F-, A-, and B-type stars in gray compared to the C/O constraints on the disk gas at the orbital radii of disk exoplanet candidates. The reported errors on exoplanet C/O are typically smaller than the plot markers, and all exoplanet values, uncertainties, and references are listed in Appendix E (Table 7).