Which of the following is a prohibited hair color for Soldiers?

The choice of fire engine red is a prohibited hair color for Soldiers because Army regulations regarding grooming standards emphasize that hair colors should appear natural and not draw excessive attention. This is in line with the Army's standards of maintaining a professional military appearance. Regulations dictate that while some variations of natural colors are allowed, vibrant or unconventional colors such as fire engine red do not conform to the requirement for hair to present a neat, clean, and professional image. The other colors mentioned—natural blonde, chestnut brown, and dark brown—are typically considered acceptable as they resemble colors found in natural hair. This understanding is crucial for Soldiers to adhere to the Army's standards and policies regarding personal grooming and appearance.