Answer:
1. My nephew's favourite food is macaroni and cheese.
2. Sandra and Martin will attend bauquet and the prom
3. i cannot go to the parade, Chris will be there.
4.
Sentence fragments are incomplete sentences that make absolutely no sense, so I'm assuming that the best answer to this questions would be B avoided when writing.
Hope this helps :)
Because it makes it easier for the person who is interested in hiring you to read, and you'll more likely be hired with a neat understandable letter.
Know who their audiacnce is