Answer:
B. The denial is justifiable given the level of interbrand competition.
Step-by-step explanation:
Anti trust law only applicable if you can proof that two or more producers in the same industry work together in order to assert their control over the market. They can do this through price fixing, controlling the amount of supply, etc.
This condition can't be found in the scenario above.
The denial that done by PepsiCo is justifiable because in a really competitive market, a company need to impose a strict requirement on which entities they should form a dealership relation with. If PepsiCo choose the wrong dealers, Its competitors could easily taken over the market and resulted in a huge amount of loss for the company.