Final answer:
The main advantage of centralized sales training is the likelihood of having highly capable training personnel, offering consistent and specialized training across the organization.
Step-by-step explanation:
The student is asking about the advantages of a centralized sales training program over decentralized approaches. Among the options provided, the answer is A: Highly capable training personnel are more likely to be available than in decentralized programs. Centralized programs can tap into specialized training staff and can ensure a consistent level of training across the organization. While B might be true in some cases, the primary advantage lies in the quality and availability of training personnel. C could also be relevant, but it is not the main advantage when compared to decentralization. Lastly, D is not correct as it stands in contrast to the main principle of centralized training, which is that specialized, not branch, managers provide better training.