Which sign color is used for mandatory instructions?

The correct answer is blue because it is the internationally recognized color used for mandatory instructions and information. In safety signage, blue indicates that certain actions must be followed and conveys that compliance is not optional. This is especially important in environments where adherence to safety guidelines is critical, such as aquatic facilities or areas where lifeguarding is practiced.

Red is typically reserved for prohibitive instructions, signaling that certain actions are not allowed. Yellow is generally associated with caution, alerting individuals to potential hazards, while green often signifies safe conditions or emergency exits rather than mandatory actions. Understanding the specific meanings of these colors helps ensure that individuals can quickly recognize and respond to safety instructions accordingly.