Final answer:
The Confederate submarine raised from the sea in 2000 off Charleston was The Hunley.
Step-by-step explanation:
The Confederate submarine that sank in 1864 and was raised from the sea bottom off Charleston in 2000 is b) The Hunley. The H.L. Hunley, often referred to simply as The Hunley, was a Confederate submarine and is known for being the first combat submarine to sink a warship, the USS Housatonic, during the Civil War.
However, The Hunley itself also sank shortly thereafter, taking its crew along with it to the bottom of the sea. It remained there until its recovery in the year 2000, providing historians and archaeologists with valuable insights into naval history.