Trainees will be in class and in _____ seat.

The correct answer is "assigned" because trainees are typically given specific seats in a training environment to ensure organization and facilitate the learning process. Assigned seating helps instructors manage the class more effectively, promoting a structured environment where trainees can focus on their training. This approach also encourages accountability and ensures that resources, such as training materials or equipment, can be distributed and organized efficiently.

Other options, while they convey certain aspects of seating preferences, do not carry the same level of formality or purpose as "assigned." Comfortable seating might imply that the trainees need to be at ease, but it doesn't reflect the organizational aspect necessary in a training setting. Preferred and personal seating suggest individual choices, which could lead to a lack of structure or disruption during classes. Using assigned seating supports a cohesive learning atmosphere that is essential for effective training.