Please answer the following question: SS Shieldhall - SS Shieldhall is a preserved steamship that operates from Southampton. She spent her working life as one of the Clyde sludge boats making regular trips from Shieldhall in Glasgow Scotland down the River Clyde and Firth of Clyde past the Isle of Arran to dump treated sewage sludge at sea. These steamships had a tradition dating back to World War I of taking organised parties of passengers on their trips during the summer. Given a choice of categories company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, the text refers to which one?
A:
Mean Of Transportation