Which of the following is not considered a transportation mode?

The answer is identified correctly because "streaming" does not refer to a mode of transportation. Instead, it pertains to the continuous transmission of data, usually associated with media such as video or audio, rather than the movement of goods or people from one location to another.

In contrast, the other options represent established physical modes of transportation. The road mode involves vehicles such as cars, trucks, and buses traveling on roads and highways. Rail pertains to the transport of goods and passengers via trains on railway tracks, which is a crucial aspect of freight and public transportation. Pipeline refers to the system of tubes used to transport liquids or gases, commonly employed for transporting oil, natural gas, and various chemicals. Thus, these three options reflect actual transportation methods utilized in logistics and commuting, while streaming does not.