Final answer:
An ankle sprain is not considered a critical injury, while unconsciousness, broken arm, and blindness are examples of critical injuries.
Step-by-step explanation:
The correct answer is A. Ankle sprain. An ankle sprain is not considered a critical injury. It is a common injury that occurs when the ligaments in the ankle are stretched or torn. Although it can be painful and limit mobility, it is not a life-threatening or severe injury.
On the other hand, unconsciousness, broken arm, and blindness are examples of critical injuries. Unconsciousness can occur due to head trauma or severe medical conditions. A broken arm involves the fracture of one or more bones in the arm, which can cause severe pain, swelling, and impaired movement. Blindness refers to the loss of vision, which can occur due to various factors such as trauma, diseases, or congenital conditions.