An unknown alkene was treated with ozone, and then Zn/H3O+. The reaction products were found to be (CH3)2CHCH2CHO and H2C=O. What is the structure of this unknown? A) (CH3)2C=CHCH2CH3 B) CH3CH2CH2CH2CH=CH2 C) (CH3)2CHCH=CHCH3 D) (CH3)2CHCH2CH=CH2 E) none of these