"<span>B). the fear among U.S. policy makers that if communism succeeded in Vietnam, it would sweep through the rest of the region" is correct. This theory was at the core of the idea of containment. </span>
Answer: Agreement / Addition / Similarity
Explanation: The transition words like also, in addition, and, likewise, add information, reinforce ideas, and express agreement with preceding material.
Both are catastrophic, so I would pick neither, but the beginning may be more enjoyable, because you get to live. At the end of the world you will most likely die.
The Black and Caspian Seas