Which of the following is NOT a type of minefield?

In the context of minefield classifications, the understanding lies in the functional purposes that various types of minefields serve during military operations.

Protective minefields are designed to safeguard specific assets or locations, such as command posts, logistical hubs, or important infrastructure. Their primary goal is to deter enemy forces from approaching these critical areas.

Defensive minefields are employed to complement the defensive strategies of military units. They are laid in front of friendly forces to disrupt or hinder an enemy's advance, providing an additional layer of defense and buying time for the unit to prepare or reposition.

Nuisance minefields serve to create confusion and irritation for the enemy. They are strategically placed to disrupt movement and compel the enemy to take longer, less effective routes or to force them into more hazardous situations.

On the other hand, 'Assault' as a type of minefield does not exist in standard military terminology. Instead, the existing categories focus on defensive and offensive attributes without directly classifying an assault type. Thus, identifying it as not a recognized classification of minefield reflects an accurate understanding of military terminology and operational doctrine.