Wrong flaw. The author’s house will be on the updated map since the map will reflect existing structures. This argument fails to recognize that a sufficient condition has, in fact, been triggered. The stimulus mistakes a sufficient condition for a necessary one.

Wrong flaw. This fails to consider that a condition which was once sufficient to establish something is a public building (a blue dot) may no longer be sufficient, since public buildings are now marked differently. The stimulus mistakes a sufficient condition for a necessary one.

No flaw. Given that the legend says that thoroughfares are marked by solid lines rather than dotted, it’s logical to conclude that the mapmakers made a mistake by marking a thoroughfare with a dotted line.

Wrong flaw. This establishes two entities that share a common characteristic—being marked with a solid line—and assumes that there’s no other way of determining which entity a particular solid line represents. The stimulus mistakes a sufficient condition for a necessary one.

This mistakes a sufficient condition for a necessary one. A hospital being located at a spot is sufficient for that spot to be marked with a purple dot, but it’s not necessary. (E) even gives an example of another kind of building could also be represented by the dot—a monument.