Which of the following is NOT a common type of martial arts class?

The choice that is identified as not being a common type of martial arts class is correct because psychological training, while potentially important in the context of martial arts, does not constitute a standalone class type. Traditional classes typically focus on established martial arts styles and techniques, incorporating the rich histories and forms of various martial arts. Freestyle classes may include a blend of techniques from multiple styles and often emphasize adaptability and improvisation during sparring. Self-defense classes are designed to teach practical applications of martial arts techniques specifically for personal safety situations.

In contrast, while psychological aspects such as mental preparedness, focus, and stress management can indeed be integral to martial arts training, they are usually embedded within the training of traditional, freestyle, or self-defense classes rather than presented as a separate class type. The focus on psychological elements does not create a distinct category that is commonly recognized on its own in martial arts training structures.