C is Mom. You can see that as time goes on the positions does not change. Mom is waiting on the doctor, not moving, so she matches this line.
A is Alexis. This line is the only one pointing down. Alexis is the only one moving downward as she walks down her driveway
Now only Dad and Aiden are left. Dad goes 1 mile while Aiden only goes .75. Of the two remaining gong lines (B and D) B is longer.
So, B is Dad and D Aiden
