Final answer:
Training and Development is the primary HR activity that equips employees with the essential skills to effectively execute their responsibilities within an organization.
Step-by-step explanation:
The primary HR activity that ensures employees have the necessary knowledge, skills, and abilities to effectively perform their tasks and duties is c. Training and Development.
This process encompasses orientation training to introduce new employees to the company policies, culture, and administrative protocols along with ongoing training that helps them master their specific job responsibilities and adapt to any new tools or duties. Performance appraisals can also serve to identify training needs and successes, but they are primarily aimed at evaluating employee performance and development rather than directly providing training.