Red Seal Carpenter Practice Exam

The unit rise and unit run for this stair are 125.0 mm and 305.0 mm respectively. This represents the vertical and horizontal distance covered by each step in the staircase. The other options are incorrect because they do not match the most commonly used standard of 7 inches (177.8 mm) for the unit rise and 11 inches (279.4 mm) for the unit run in building codes. Option A has a larger unit run, which could result in uneven steps and difficulty in climbing the stairs. Option C has a larger unit rise, which could potentially lead to taller and more strenuous steps. Option D has a much larger unit rise compared to the unit run, which is not recommended for safety reasons. Therefore, option B is the most appropriate and commonly used measurement for the unit rise and unit run in a staircase.