Which of the following is NOT a firing formation used in mortar operations?

In mortar operations, various firing formations are utilized to optimize the effectiveness of the weapon system. The circle formation is not recognized as a standard firing formation in mortar tactics. The common formations used include parallel, diamond, and triangle.

In a parallel formation, mortars are arranged side-by-side to allow for a broad coverage area and to deliver fires on a specific target efficiently. The diamond formation allows for a more concentrated firepower while maintaining effective dispersion of mortars, which can enhance survivability and coordination. The triangle formation, while less common than the other two, also facilitates overlapping fields of fire, providing flexibility and allowing for quick repositioning.

Using a circle, however, does not serve a practical purpose in terms of the geometric advantage or operational efficiency perceived in traditional mortar firing formations. Therefore, identifying the circle as an incorrect choice underlines a fundamental understanding of effective mortar deployment strategies in the field.