The correct answer is option 4: Aral Sea. A landlocked sea refers to a sea that is completely surrounded by land, with no direct access to the open ocean. The Aral Sea, located between Kazakhstan and Uzbekistan in Central Asia, fits this description. It is actually a closed basin and does not have any natural outflow, meaning that water flows into the sea but does not flow out. This has led to the shrinking of the Aral Sea over the years, as water has been diverted for irrigation purposes, resulting in severe environmental and ecological consequences. The other options given do not meet the criteria of being landlocked seas. The Timor Sea, Arafura Sea, and Greenland Sea are all open to the ocean and connected to larger bodies of water.