What structural feature indicates unreinforced masonry in brick construction?

The presence of a king's row every six courses is a notable feature in unreinforced masonry. In brick construction, a "king's row" refers to a row of headers, which are bricks laid horizontally but turned on their ends to span across the wall. This design helps to bond the structure and distribute loads effectively but is typically seen in unreinforced masonry as a traditional building technique.

In unreinforced masonry, the structural integrity is primarily reliant on the weight of the bricks and the arrangement of courses, rather than additional reinforcement. The king's row serves as a method of interlocking bricks, enhancing stability without the aid of steel or concrete reinforcements, which are found in reinforced masonry systems.

The other options, such as concrete cores, wooden beams, and steel reinforcements, represent features associated with reinforced masonry or other construction methods, which do not indicate the characteristics or traditional practices of unreinforced masonry.