Please answer a question about the following article about Southampton:

Southampton used to be home to a number of ferry services to the continent, with destinations such as San Sebastian, Lisbon, Tangier and Casablanca. A ferry port was built during the 1960s. However, a number of these relocated to Portsmouth and by 1996, there were no longer any car ferries operating from Southampton with the exception of services to the Isle of Wight. The land used for Southampton Ferry Port was sold off and a retail and housing development was built on the site. The Princess Alexandra Dock was converted into a marina. Reception areas for new cars now fill the Eastern Docks where passengers, dry docks and trains used to be.

What has the Princess Alexandra Dock become?
a marina