… in his right senses will swallow live coals.

Analyze the question: The sentence is "......... in his right senses will swallow live coals." We need the word or group of words that makes the sentence logical and grammatically correct.

Concept: This tests meaning and logic in sentence completion. Swallowing live (burning) coals is harmful and absurd, so the sentence must express that a sane person would not do it. The phrase "in his right senses" means "sane" or "mentally sound."

Step-by-step solution:

1. A. Anyone – "Anyone in his right senses will swallow live coals" says a sane person will do it. This is illogical, so it is wrong.
2. B. No one – "No one in his right senses will swallow live coals" says a sane person would never do it. This is logical and grammatically correct.
3. C. Everyone – This claims all sane people will swallow live coals, which is absurd.
4. D. Each one – This is also illogical, and it is incomplete without a reference such as "each one of them."

(Note: "Anyone" would work if the verb were negative, as in "Anyone in his right senses won't swallow...", but the sentence has a positive verb "will," so a negative subject is needed.)

Answer: B. No one

Tip: In sentence completion, first read the whole sentence for meaning. Ask: "Is this a sensible thing to say?" Phrases like "in his right senses" usually pair with a negative idea, such as "No one in his right senses would..."