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