You will be given a definition of a task first, then some input of the task.
This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Charleston is the oldest and second-largest city in the U.S. state of South Carolina, the county seat of Charleston County, and the principal city in the Charleston–North Charleston–Summerville Metropolitan Statistical Area. The city lies just south of the geographical midpoint of South Carolina's coastline and is located on Charleston Harbor, an inlet of the Atlantic Ocean formed by the confluence of the Ashley and Cooper Rivers, or, as is locally expressed, "where the Cooper and Ashley Rivers come together to form the Atlantic Ocean."
Output:
What is the oldest city in South Carolina?