Hi, the answer is C but I’m not sure with reasoning / concept.
When larger alkane molecules are cracked, they form smaller alkane molecules and alkene molecules.
general formula of Alkanes are 2n+2 , so this gives opt A and D
general formula of Alkenes are 2n so this gives opt B and E
Moreover, Hydrogen could also be formed so this rules out opt F too.
Opt C is not an alkane or alkene so that would be the answer.