Answer:
B. Only if they are older than six-years-old
Explanation:
This question would need to be more specific, in regards of which State are we talking about.
I'll try to answer this question in the more general way considering all the United States state's laws considering this matter in a general way.
In the United States every state has different laws regarding leaving children unattended in the car. Some states state that the children must be older than 6 year old and some of them say that they must be older than 9 year old. Some states don't even have laws regarding this matter.
However, NONE of the states say that it is legal or okay to leave children younger than 6-years-old, they also don't say it's okay as long as the windows are rolled down or the keys are not in the car.
Therefore, the correct answer would be b. since it's the only one that is mentioned in some state's laws such as Florida, Illinois or Louisiana.
