Which of the following is a crucial item for showmanship preparation?

Proper grooming supplies are essential for showmanship preparation because they play a significant role in demonstrating the overall care and presentation of the animal. In a competitive showmanship context, how well the animal is groomed can significantly impact the judge's perception. Grooming supplies include items such as brushes, combs, clippers, and bathing products, which help to ensure the animal is clean, well-maintained, and presented in the best possible condition. This attention to detail reflects the exhibitor's commitment to quality care and can enhance the appeal and overall impression of the animal during the show.

While extra feed, additional trainers, and comfortable footwear may have their importance in the broader context of show preparation, they do not impact the grooming aspect, which is critical for optimal show presentation and success in the ring.