It seems theres multiple things by the name ARC. There is one by AI2 which is a text based science questions/word problems. The one Im referring to is this
https://lab42.global/arc/https://lab42.global/arcathon/leaderboard/
https://openreview.net/forum?id=E8m8oySvPJ
As to the study, I have the same objection as the radiology one. This isnt about object recognition and certainly not spatial reasoning, its the ability to predict cancer based on presence of visual features.
The "object recognition" part of this is super simple. Its a single, mostly 2D object in more or less the same angle, and the AI is trained on detecting just this.