Struggling steel pipe makers including United States Steel Corp, Tenaris SA subsidiary Maverick Tube Corporation, JMC Steel Group Inc's Energex Tube, Russia's TMK IPSCO and France's Vallourec Star filed the case in 2013, saying OCTG imports had been sold cheaply to the United States using government subsidies.
Analyze the relationship between 'Tenaris' and 'pipe' within the context of the input sentence.
Options: product/material produced, chairperson, headquarters location, manufacturer