Final answer:
Barbara should slow down to comply with the speed limit.
Step-by-step explanation:
If Barbara is a responsible citizen, she should choose option b) Slow down to comply with the speed limit.
It is important to obey the speed limit for several reasons. Firstly, driving at a safe and legal speed reduces the risk of accidents. Speeding can make it harder to control the vehicle and increases the stopping distance, which can result in collisions. Secondly, speeding is against the law and can lead to traffic violations and fines. Lastly, driving at a safe speed ensures the well-being of other road users, including pedestrians and cyclists, who may be put at risk by excessive speed.