Answer :
. Charles Dickens was a British author who wrote Oliver Twist, David Copperfield, and Great Expectations.
Punctuation is used to structure and organize the writings. It helps in making more sense and clarity in the sentence.
The sentence which is written correctly is Charles Dickens was a British author who wrote Oliver Twist, David Copperfield, and Great Expectations.
This sentence is correct because it uses the punctuation mark comma appropriately to make logical groupings. Also, it helps in segregating one list from another. Hence, the above sentence comma is used to separate a series of phrases.