The History of Popcorn

(1) Popcorn is a snack that can easily be popped in a microwave for three minutes, with little thought given to where it originated. (2) In fact, without corn, a staple in the Americas, we could not eat the delicious snack that popcorn is. (3) Evidence suggests that popcorn arrived in the American Southwest over 2,500 years ago; however, it was not easily grown east of the Mississippi until the early 1800s due to poor soil quality.
(4) Indigenous peoples domesticated the type of corn that produces popcorn around 5000 BCE. (5) This domesticated corn has kernels so tough that they cannot be chewed. (6) To experience the soft edible inner portion of a kernel of corn, the kernel must be heated, and when heat and steam cause the kernel to burst, the soft flakes that we know as popcorn are released.
(7) Popcorn as a snack did not appear in the United States until the 1820s. (8) The popularity of popcorn quickly spread across the South around the 1840s. (9) By 1848, the word popcorn was included in John Russell Bartlett's Dictionary of Americanism. (10) According to Bartlett, the word comes from the sound that corn makes when bursting open.
8
Which change should be made to sentence 9?
A.
Change was included to is included.
B.
Italicize the book title Dictionary of Americanism.
C.
Remove the apostrophe in Bartlett's.
D.
Remove the comma after 1848.