look at the map. explain why elm street and birch street are not perpendicular

I cannot see the choices, so, I will explain this using two different concepts and you can apply the explanation on the given choices

1- Explanation using angle formed:
Imagine that Elm street and Birch street are two lines.
Now, for to lines to be perpendicular, these two lines must intersect forming a 90 degree angle.

Now, noticing the intersection between the two streets, we will find that the angle, formed is not 90 degrees

2- Explanation using slopes:
For two lines to be perpendicular, the slopes of the two lines must be negative reciprocals of each other.
This means that, if the slope of one line is m, then the slope of the other must be -1/m for the two lines to be perpendicular.

Now, Birch street is a horizontal line, this means that its slope is zero.
For Elm street to be perpendicular on it, the slope of Elm street must be equal to -1/0. This means that the slope of Elm street has to be undefined which means that Elm street must be a perfectly vertical line.

However, from the graph, we can note that Elm street is an inclined line which means that its slope is not undefined.
This means that the two streets are not perpendicular to each other.

Hope this helps :)