I have recordings by Zoltan Kocsis and Monique Haas. Both play d there. (My only score is the Dover reprint of the Fromont edition, supposedly "with corrections by Beveridge Webster", showing d for that note.) Personal opinion: d seems to work okay, and Debussy often puts small mysterious variations in returning phrases in the early works, so I would assume d is "correct" in the absence of authoritative contrary evidence. But if you like c better there, just play it.