Hi there!
We are looking for perpendicular angles, which means the angle between the streets is 90 degrees. So, each time we need to find the street that intersects the given street with a 90 degree angle.
On this map, Oxford Street is perpendicular to Waterloo St., and Rosewood Street is perpendicular to Oak St..
The answers are (in correct order): Waterloo St. and Oak St..
~ Hope this helps you!