Final answer:
The correct spacing range for ladder rungs/steps is 10 to 14 inches, which is important for safety and ergonomic reasons in occupational health.
Step-by-step explanation:
The rungs/steps spacing range for portable and fixed ladders (not including step stools) is Option 1: 10 to 14 inches. It's important to adhere to this range to ensure safety and compliance with standards. The reference to stepping heights and distances is related to the overall ergonomics of climbing a ladder, ensuring that each step is within a safe and comfortable range for the average person's stride and leg length. Ladder safety is a critical aspect of occupational safety and health standards.