Which type of joint is formed, sawed, or tooled to create a controlled location of cracking in concrete?

The correct choice, which is the contraction joint, refers to joints that are deliberately created in concrete to control cracking that can occur as the material shrinks and contracts due to temperature changes and moisture loss. By cutting these joints into the concrete surface, typically while the concrete is still curing, it allows for controlled cracking to happen at predetermined locations, rather than randomly throughout the slab. This ensures structural integrity and aesthetic quality, as it minimizes the visible cracking in more crucial areas.

An isolation joint differs in that it separates different structural elements, allowing them to move independently without transferring stress. Expansion joints are designed to accommodate the expansion of concrete due to heat, rather than to control cracking from shrinkage. Control joints, while similar in intent to contraction joints, more broadly refer to joints that are installed in concrete to manage cracking but do not specifically account for contraction in their naming. Therefore, the specific terminology of "contraction joint" directly aligns with the function of controlling cracking due to concrete shrinkage, making it the accurate choice in this context.