Question

what should you do if you see someone having an allergic reaction?
ask for a refund
call 9 - 1 - 1
consult with public health for advice
give them some water

Explanation:

When someone is having an allergic reaction, it is a medical emergency. Calling 9 - 1 - 1 is the most appropriate immediate action as it connects to emergency services that can provide professional medical help quickly. Asking for a refund is irrelevant to an allergic reaction situation. Consulting with public health for advice may take too long in an emergency. Giving them water could be dangerous if the person's airway is compromised.

Answer:

Call 9 - 1 - 1