What is the major product obtained on acidification of substituted epoxide?
The reaction of epoxyketone 1 affords diketone 2 under photochemical and thermal conditions ostensibly through the diradical.1 Boron trifluoride provides the diketone 3 through acyl bond migration and not via alkyl group migration as in your intermediate 3a. I have not located a proton-catalyzed reaction. Unfortunately, diketone 3 was not one of your choices.


1) John R. Williams, George M. Sarkisian, James Quigley, Aaron Hasiuk, and Ruth VanderVennen, J. Org. Chem., 1974, 39, 1028.