Answer:
a. larger pipe diameters
Explanation:
This is the factor that allows pipelines to increase their capacity and move an increased amount of tonnage. When we increase the diameter of a pipe, this allows a larger volume of material (water, oil, etc.) to move through it. This means that we are able to move a larger volume (tonnage) of material in a shorter amount of time. This increases the efficiency of the pipelines in a very significant way.
