The prevention of accidents makes it necessary not only that safety devices be used to guard exposed machinery but also that mechanics be instructed in safety rules which they must follow for their own protection, and that lighting in the plant be adequate.

The passage best supports the statement that industrial accidents -

The passage discusses the prevention of industrial accidents, emphasizing the use of safety devices, proper training in safety rules for mechanics, and adequate lighting in the plant. Here's the analysis of the options based on the passage:

1. Option A - are always avoidable:
   • The passage does not claim that industrial accidents are always avoidable. It discusses preventive measures to reduce accidents, but does not state that all accidents can be avoided under any circumstances.
   • This option is not supported by the passage.
2. Option B - may be due to ignorance:
   • The passage suggests that mechanics must be instructed in safety rules, implying that ignorance of these rules may lead to accidents. This aligns well with the idea that accidents may occur due to lack of knowledge or awareness.
   • This option is strongly supported by the passage.
3. Option C - cannot be entirely overcome:
   • The passage does not explicitly state that accidents cannot be entirely overcome. It focuses on the prevention of accidents through safety measures, implying that prevention efforts can reduce accidents but does not rule out complete elimination.
   • This option is not fully supported by the passage.
4. Option D - can be eliminated with the help of safety rules:
   • The passage does emphasize the importance of safety rules in preventing accidents, but it does not claim that accidents can be completely eliminated. It talks about reducing accidents through safety measures, not total elimination.
   • This option is partially supported but not fully aligned with the passage.
5. Option E - usually result from inadequate machinery:
   • The passage does not mention that accidents are usually due to inadequate machinery. It discusses safety measures such as safety devices, rules, and lighting, but does not focus on machinery as the primary cause of accidents.
   • This option is not supported by the passage.
6. Final Answer:
   • The most supported statement by the passage is B. may be due to ignorance.