Read the following passage and answer the questions that follow .
Vehicles do not move about the roads for mysterious reasons of their own. They move only because people want them to move in connection with the activities which the people are engaged in. Traffic is therefore a ‘function of activities’, and because, in towns, activities mainly take place in buildings, traffic in towns is a ‘function of buildings’. The implications of this line of reasoning are inescapable.
The author says that traffic is a ‘function of activities’. He means that

Options

A. human activities are taking place.
B. human activities are dependent on traffic.
C. traffic is not dependent on human activities.
D. traffic is connected with human activities.