Final answer:
d. Poor window installation. The step cracks in a masonry wall at the top corner of a window angled up and away are typically caused by poor window installation.
Step-by-step explanation:
The step cracks in a masonry wall at the top corner of a window angled up and away are typically caused by d. Poor window installation.
When a window is poorly installed, it can result in uneven stress distribution on the masonry wall. As a result, cracks may form, particularly at the weakest points such as the top corners of the window. These step cracks can gradually worsen over time if not addressed.
To prevent step cracks and ensure proper installation, it is important to hire a professional window installer who follows industry guidelines and uses appropriate techniques to secure the window and distribute the weight evenly.