A sign shows a symbol inside a red circle with a slash across it. What does the sign tell you?

1. 1The action shown is allowed
2. 2The action shown is not allowed
3. 3The action shown is the only choice
4. 4The action shown is only a suggestion

Source: Nova Scotia Driver's Handbook (Service Nova Scotia, 2000, reprinted with revisions to 2017), Chapter 3, Signs, Pavement Markings, and Work Zones: Signs with a red circle, page 79