What coefficient should be written in front of the reactant oxygen gas (o2) in order for this equation below to be balanced?

c2h4 + o2 --> 2co2 + 2h2o

C₂H₄ + 3O₂ --> 2CO₂ + 2H₂O

Explanation:

In products side we have 4 oxygens from the 2 moles of CO₂ and 2 oxygens from the 2 moles of water. In total, we have 6 O, so as we have 3 atoms of oxygen in reactant side, we must have 3 moles to complete the 6 O.

In reactant side we have 2 C

In product side we have 2 C

In reactant side we have 4 H

In product side we have 4 H ( 2 .2, in water)

In reactant and in product side, we have 6 O

i need mutiple choices