Final answer:
A high task, high relationship manager is most likely to be effective in handling the employee's performance gap.
Step-by-step explanation:
The style of manager most likely to be effective in handling the employee's performance gap is C. High task, high relationship. A high task manager focuses on achieving goals and objectives, while a high relationship manager prioritizes building strong relationships with employees. In this case, the manager needs to both ensure the legal requirements are met (high task) and provide support and guidance to help the employee navigate the changes (high relationship).