Final answer:
Sentence 6 should be rewritten as 'Our coach, wrapped up in the demonstration he was giving, did not even notice his mistake.' to correctly set off the explanatory clause with commas and maintain sentence flow.
Step-by-step explanation:
The best way to rewrite sentence 6 to ensure proper use of commas for clarity and to correct the sentence structure would be option d: "Our coach, wrapped up in the demonstration he was giving, did not even notice his mistake."
This option correctly uses a pair of commas to set off the explanatory clause "wrapped up in the demonstration he was giving" within the sentence.
The commas indicate a brief pause and provide additional information about the coach while maintaining the flow of the original statement.
Sentence 6 should be rewritten as follows: d. Our coach, wrapped up in the demonstration he was giving, did not even notice his mistake.
The original sentence is grammatically incorrect because it doesn't include a comma after the introductory phrase 'wrapped up in the demonstration he was giving'.
By adding the comma, it clarifies that the coach was focused on the demonstration and therefore didn't notice his mistake.