You have seen the structure of acetylacetone before. Note that the carbonyl groups are not aligned to avoid repulsion between the dipole associated with the carbonyls. Now, let's examine whether this structure contains enolizable hydrogen-atoms. Of course, you can easily find two types of enolizable H-atoms; six on the methyl groups and two on the central methylene group. The questions is which one is more likely to become involved in tautomerization?