In which of the following locations in concrete masonry should a control joint be placed?

Control joints in concrete masonry walls are designed to accommodate movement caused by thermal expansion, moisture changes, and settlement.

Control joints should be placed at locations of stress concentration, such as changes in wall height, changes in wall thickness, or at large wall expanses.

They are not placed at the first course of masonry (which is typically reinforced and anchored to the foundation).

They are generally not placed at window corners or in the center of window openings but rather at planned intervals or changes in geometry.

Placing a control joint at changes in wall height allows movement without cracking.