Which sentence best shows correct comma usage?

a.
native american groups include the mayan, the aztec and the toltec people.

The sentence that best shows correct comma usage is: D) Native American groups include the Mayan, the Aztec, and the Toltec people.

Explanation:

The question is not complete since it does not provide the options to answer it, here are the options:

A) Native American groups include the Mayan the Aztec, and the Toltec people.

B) Native American groups, include the Mayan the Aztec and the Toltec people.

C) Native American groups include the Mayan, the Aztec and the Toltec people,

D) Native American groups include the Mayan, the Aztec, and the Toltec people.

One of the uses of comma is to connect the words that go included in a list, this sentence in order to be correct needs to have a comma after each one of the nouns to make them part of a list of names of cultures, it is also necessary to put a period at the end of the list, that means that option D is the only one that uses it correctly.

closer examination, however, finds the mcdonald's kind of job highly uneducational in several ways. far from providing opportunities for entrepreneurship (the lemonade stand) or self- discipline, self-supervision, and self-scheduling (the paper route), most teen jobs these days are highly structured — what social scientists call “highly routinized.”  

true, you still have to have the gumption to get yourself over to the hamburger stand, but once you don the prescribed uniform, your task is spelled out in minute detail.  

the answer is c bro ok