In the context of gasoline formulation, identify the primary technical reason phenolic additives are used—considering effects on octane, oxidation stability (gum control), viscosity, and pour point.

Introduction:
Gasoline degrades by oxidation, forming peroxides and gums that foul fuel systems. Phenolic additives (e.g., hindered phenols) are classic antioxidants used to improve storage stability and limit gum formation.

Given Data / Assumptions:

• Gasoline base fuel prone to oxidative gum formation.
• Phenolic additives considered for performance.

Concept / Approach:
Oxidation inhibitors interrupt radical chain reactions. Phenols donate hydrogen to stabilize fuel radicals/peroxides, slowing gum formation. Octane effects are secondary; viscosity and pour point are largely unrelated in gasoline.

Step-by-Step Solution:

Verification / Alternative check:
Standard gasoline additive packages list phenolic antioxidants specifically for gum control and oxidation stability metrics (e.g., induction period tests).

Why Other Options Are Wrong:

Common Pitfalls:
Confusing antioxidant function with octane boosters or cold-flow improvers used in diesel/lube oils.

Final Answer:
Act as an antioxidant (reduce gum formation)