The Smith Family The Smith Family Is Sitting Around the Table, Talking About

The Smith Family
The Smith family is sitting around the table, talking about their upcoming family vacation to the Rocky Mountains. Jack and Diane are the parents, and they are both in their 30s. They have two children. Brian is 15 years old, and Betsy is 8 years old. Diane doesn't know it yet, but she's also about three weeks pregnant with a third child. As they are all discussing the trip, Betsy suggests that they go on a helicopter tour of the mountains like the one that she saw on TV. Jack and Diane tell Betsy that they can't afford that kind of trip this year, but they give Betsy a travel guidebook and tell her that she could pick out an activity for the family that costs less than $100. Brian tells his parents that he went online to one of the travel websites and plotted out several different routes for driving to their destination. He shows them how he compared different ways of getting there (distance, time of travelling, and landmarks) , and explains that the route that he planned was a combination of shortest time of travelling but with a few deviations to see some interesting places. Betsy thinks this is a great idea so that the car doesn't get bored on the way there!
-What cognitive stage would Piaget suggest that Brian has achieved,based on his ability to systematically evaluate and plan the driving route

A)  sensorimotor 
B)  preoperational 
C)  formal operational 
D)  concrete operational