Final answer:
The most influential variables in Path-Goal Theory for selecting a leadership style are follower nature and task nature. Therefore, the correct option is C.
Step-by-step explanation:
In Path-Goal Theory, the most influential variables in selecting a leadership style are follower nature and task nature. This means that a leader's choice of style should be based on the characteristics of the followers and the specifics of the task at hand. For instance, employees who are autonomous may resist a high amount of structure, while those who need more guidance benefit from clear responsibilities and little role ambiguity. On the other hand, the nature of the task also plays a crucial role; tasks that are complex or ambiguous may require a leadership style that offers more direction and support. Therefore, the correct answer to this question is C. follower nature and task nature.