Final answer:
Option C, which focuses on employee selection and retention, is not directly related to the strategy execution process, which involves leadership, resource allocation, best practices, and corporate culture.
Step-by-step explanation:
The question asks which of the listed options is not among the principal managerial components of the strategy execution process. The correct answer is C. Selecting and retaining capable employees, thereby enhancing the company's intellectual capital resources. This option does not directly relate to the execution of a strategy but is more concerned with human resources management. The other options, such as exercising strong leadership (A), marshaling resources (B), instituting best practices (D), and instilling a corporate culture (E), are all key components of strategy execution as they pertain directly to the processes, resources, and culture needed to implement a chosen strategy effectively.