Which of the following must instructors teach regarding tack?

Instructors must teach the proper fitting and care of tack and equipment because understanding how to correctly fit tack is essential for the safety and comfort of both the horse and the rider. Proper fitting ensures that the tack does not cause discomfort or injury to the horse, which can lead to behavioral issues or physical harm.

Additionally, instructors should cover the care of tack as it plays a crucial role in the longevity and effectiveness of this equipment. This includes cleaning, conditioning, and maintaining the tack to ensure it remains safe for use. Teaching these aspects builds foundational knowledge for students, enabling them to manage their equipment responsibly and effectively.

The other choices focus on aspects that are not as fundamental for riding instruction. For instance, purchasing tack, while important, is secondary to understanding fit and care. Painting custom designs, although a creative skill, does not pertain to the primary safety and performance concerns of tack. Maintaining equipment in good condition is important, but it is incorporated within the broader context of care and fitting that must be emphasized in instructional settings. Therefore, understanding both proper fitting and care collectively equips students with the necessary skills for responsible riding practices.