Which of the following styles is prohibited for facial hair?

The answer is correct because handlebar mustaches are often not permitted under many police department grooming policies, including typically more structured or formal environments like law enforcement. These policies usually emphasize a neat, uniform appearance that reflects professionalism and authority. Handlebar mustaches, which are characterized by their distinctive upward-curving ends, can create a non-traditional or flamboyant look that detracts from the uniformity desired in police personnel.

In contrast, other styles such as a full set beard, stylish mustache, or neatly trimmed goatee may be acceptable as long as they meet the grooming standards established by the department. These alternatives can often be groomed to appear tidy and professional, aligning more closely with the organization's requirements for facial hair.