The correct answer is: A. road side interview method
The roadside interview method is the preferred method for collecting origin and destination data for a small area like a mass business center or a large intersection. This is because it is a relatively inexpensive and efficient way to collect data from a large number of people. The roadside interview method involves stopping people at random as they enter or leave the area of interest and asking them about their travel habits. This data can then be used to create origin and destination matrices, which are used to model traffic flows.
The other options are not as effective for collecting origin and destination data for a small area. The license plate method involves collecting data on the license plates of vehicles entering and leaving the area of interest. This data can then be used to track the movements of vehicles, but it does not provide information on the origin and destination of individual trips. The return postcard method involves mailing postcards to residents of the area of interest and asking them to return the postcards with information on their travel habits. This method is relatively low-cost, but it has a low response rate. The home interview method involves interviewing residents of the area of interest in their homes. This method is the most accurate way to collect origin and destination data, but it is also the most expensive and time-consuming.