Number 4: She has six Aunts, five Uncles, and fifteen cousins, has a capitalization error.
Aunts and Uncles should be lower cased because they are common nouns. They describe the people who are the aunts and uncles. However, if you had a name that followed aunt (like in number 5), then Aunt and the name of the person would be capitalized because it is a title of a person and it becomes a proper noun.
Hopefully this helped.
D. because " was a lot of fun" is a prepositional phrase.
