Question

You shouldn't use commas in a sentence where items in a series are joined by

a. A semicolon
b. A conjunction
c. Any preposition
d. An adverb or an adjective

Answer 1

b. a conjunction.
ex: I ate cookies, icecream, and cake. (commas)

I ate cookies and icecream and cake. (no commas)

Answer 2

b. A conjunction

Step-by-step explanation:

Commas are used to separate items in a list or series of things. However, when these items are joined by a conjunction like or, and, or as well os, the comma is not necessary because conjunction already provides a smoother transition from one word or idea to another.

Take a look at the following examples:

The sweater is green, and blue. (Incorrect, the comma is unnecessary)

The sweater is green and blue. (Correct)