Answer :
Final answer:
The non-mandatory guidelines suggest guardrail posts should be 2x4 lumber spaced 6 feet apart with midrails also made from 2x4 lumber. Answer option a) is correct.
Explanation:
According to the non-mandatory guidelines plan, guardrail posts should be made of at least 2x4 lumber spaced 6 feet on center and the midrail made of at least 2x4. Therefore, the correct answer to the question is: a) 2x4, 6, 2x4. Guardrails are an important safety feature in construction and other industries where employees may be exposed to falls or elevated work areas. The specified dimensions and spacing ensure a strong and effective barrier against accidental falls.