Answer:
C.
structural safety
Explanation:
Guards protecting floor surfaces must be 36 inches in height, while guards for stairs must be 34 inches in height measured vertically from the tread nosing. A guard may also serve as the required handrail (34 to 38 inches high) provided the top rail meets the requirements for grip size.
I believe the answer is D: brazing
Hope this helps you have a good night