Please answer the following question: USS Vigil (AGR-12/YAGR-12) was a Guardian-class radar picket ship acquired by the U.S. Navy in 1956 from the mothballed reserve fleet. She was reconfigured as a radar picket ship and assigned to radar picket duty in the North Atlantic Ocean as part of the Distant Early Warning Line. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
Answer:
Mean Of Transportation