Answer:
See figure 1
Explanation:
In this question, we have to remember that each carbon has 4 electrons and each hydrogen has 1 electron. Additionally, the structure proposed have to have 8 electrons for each atom (except hydrogen). With this in mind, we need to have a double bond between the carbons, because in this arrangement each carbon would have 8 electrons (octet rule).
See figure 1
I hope it helps!