Answer:
C. <em>His friend's house, grocery store, and his home.</em>
Step-by-step explanation:
Triangle Proportionality Theorem-
If a line parallel to one side of a triangle intersects the other two sides of the triangle, then the line divides these two sides proportionally.
So if the line joining the park, bus stop and friend's house, grocery store will be parallel, Stephen can use triangle proportionality theorem.
When two lines are crossed by another line i.e the transversal, the angles in matching corners are called corresponding angles. And when the corresponding angles are equal then the two lines are parallel.
The corresponding angle of the angle between the park, the bus stop, and his home is the angle between his friend's house, grocery store, and his home.
Therefore, he needs to measure that angle.