Respuesta :
A-The circus features four clowns, three acrobats, and a tightrope walker.
E-The flags are blue and white; red, white, and blue; and red, white, and green.
E-The flags are blue and white; red, white, and blue; and red, white, and green.
The answer to your question would be that the sentences that are punctuated correctly are the following ones: The circus featured four clowns, three acrobatas, and a tightrope walker and the flags are blue and white; red, white and blue; and red, white, and green. That is, your answers woud be A and E.
The comma used in these sentences is known as the Oxford comma. This comma is the final comma in a list of things. The use of the Oxford comma is up to you. Still, omitting it can cause misunderstandings, such as in D.
d) I wrote poems about my best friends, the queen of England and the tooth fairy
D is understood as if the speaker's best friends were the queen and the tooth fairy.