B is the answer it is correct I took this test thank you
<span>The answer is:</span>
C. Sentence 1
<span>The
sentence “Earth's crust is made up of relatively rigid plates that
ride atop Earth's hot, semiliquid mantle.” Is the topic sentence because it
connects all the other sentences to its main idea. They entire paragraph is
related and can be a subtopic of this sentence, which is the purpose of a topic
sentence.</span>
Answer: Its A.
Explanation: I'm just that smart! Hope this helps!
The crowd, because it identifies a group of people and still sounds like a singular noun.