What Is the Stoichiometric Coefficient for Oxygen When the Following

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest, whole-number coefficients?
________ C₃H₆O(l) + ________ O₂(g) → ________ CO₂(g) + ________ H₂O(l)

A) 1
B) 3
C) 5
D) 4