The reaction of cyclooctyne with HgSO4 in the presence of aqueous H2SO4 gives A. B. C. D.

The correct answer is A.

The reaction of cyclooctyne with HgSO4 in the presence of aqueous H2SO4 gives 1-octyne-1,6-dione. This is a Diels-Alder reaction, in which the two double bonds in cyclooctyne react with the sulfur dioxide molecule to form a six-membered ring. The sulfur dioxide molecule is activated by the HgSO4 catalyst, which makes it more reactive.

Option B is incorrect because it does not have the six-membered ring that is formed in the Diels-Alder reaction. Option C is incorrect because it has a different number of carbon atoms than cyclooctyne. Option D is incorrect because it has a different functional group than 1-octyne-1,6-dione.