You are driving on the road in the picture and have forgotten what speed limit was on the sign. How should you react?
You should first assume that you are driving in a built-up area, because the picture shows many buildings close to the road.
“Within a built-up area, a vehicle may not be driven at a higher speed than 50 kilometres an hour.” (Swedish Road Traffic Ordinance)
Review of the options:
Another way of looking at it: There are both road signs and regulations that indicate maximum speed limits. You shall firstly adhere to the road signs, but if you have forgotten these it is reasonable to “fall back” on the regulations, which state that a maximum speed limit of 50 km/h applies within a built-up area. This is much more reasonable than panicking and braking dangerously.