Answer: B. restricting the use of cars in the main city centers.
Step-by-step explanation:
Cittaslow is an organization that aims to improve the standard of life by reducing the pace at which life goes in urban areas. This stems from the belief that fast paced life leads to stress and other negative effects.
As Cittaslow aims to slow down a fast-paced life, this includes slowing down traffic as well so they advocate for the restriction of the use of vehicles in the main city centres to reduce traffic.