Balance the Equation C₈H_18(l)+ ___ O₂(g)→ ___ CO₂(g)+ ___ H₂O_(l)

Balance the equation C₈H_18(l) + ___ O₂(g) → ___ CO₂(g) + ___ H₂O_(l) .
What is the coefficient for O₂(g) ?

A) 16
B) 9
C) 25
D) 12
E) 50