Answer:
Option B
Step-by-step explanation:
Remember that the products are on the right side of a chemical equation while the reactant is on the left.
In this case we have...
C2H6 + O2 ⇒ CO2 + H2O
Since C2H6 and O2 are on the left side that would mean they're the reactants, while CO2 + H2O are the products. Which means your answer is option B or "C2H6 + O2 are the reactants, CO2 + H2O are the products."
Hope this helps.