25. What starting materials would be suitable for preparing this compound by a combination of Michael and aldol reactions?  
(A) 4-methyl-2-cyclohexen-1-one and 3-butenal
(B) 2-methylcyclohexane-1,3-dione and 3-buten-2-one
(C) 2-methyl-2-vinyl-3-cyclohexen-1-one and acetaldehyde
(D) 2-methyl-2-cyclohexen-1-one and 1,4-dichlorobutan-2-one
(E) 4-methylcyclohexnone and methyl vinyl ketone