Emily and Tamra are both proper nouns. Careful is an adverb. Stuff is a noun. Is is a verb. With is a preposition. And always is an adverb.
Not a complete article, but:
Pros: You get places faster, more efficiently
Cons: Pollution, car crashes
A paragraph in an essay and NOT an example of insertion.
The answer is D. Remain.
Happy Studying! ^=^