Are the commas placed correctly in (A) or (B)?

(A) The reason is often that the interviewer wants an overview, or opening statement summarizing how your skills, experiences and background are a good fit for the internship.

(B) The reason is often that the interviewer wants an overview, or opening statement summarizing how your skills, experiences, and background are a good fit for the internship.

I think (B) is correct.

Likewise, which is correct?

(C) John buys apples, oranges, pears and grapes.
(D) John buys apples, oranges, pears, and grapes.

I think (D) is correct.

Thank you for your assistance!

Wow! Who knew that the oxford comma was so important?

But I have a sweatshirt that says,
"Let's eat, Grandma.
Let's eat Grandma.
Commas save lives"

I don't think either A or B is correct. A is certainly incorrect; B could be correct if the first comma (the one before "or") were not there.

Yes, D is correct.

All of those examples are correct. The comma before the "and" is known as the oxford comma. Some style books prefer it; some don't. Unless you're writing for a publication of teacher that has expressed a preference, the choice is up to the writer.

https://www.grammarly.com/blog/what-is-the-oxford-comma-and-why-do-people-care-so-much-about-it/

I know what Ms. Sue is saying is right. It depends on your teacher and/or on the style guide you are to follow.

There's a company in Maine, however, that learned the hard way how costly it can be if the Oxford comma is omitted!
https://www.nbcnews.com/news/us-news/think-commas-don-t-matter-omitting-one-cost-maine-dairy-n847151

Excellent!!

You are correct!

In the first example, (B) is the correct option. The commas should be placed before each item in a list, including the last one. So, in this case, it should be "skills, experiences, and background."

Similarly, in the second example, (D) is the correct option. The commas should be placed before each item in a list, including the last one. So, it should be "apples, oranges, pears, and grapes."

You're welcome! If you have any more questions, feel free to ask.