White oak...andit not only matters which acorn, but which tree. Deer seem to have a keen memory when it comes down to remembering where thebiggest beechnuts,sweetest acorns, or juiciest apples fall
Miller and Marchinton have done studies on food preference, run a literature search. Those two (with others) have also documented which tree species bucks prefer for rubbing...
AND...you can always just try the different yourself. You'll quickly determine why deer prefer white oak compared to the reds...[:'(]