<span>A topic sentence is the central idea of a paragraph, while a main idea is the central idea of an entire text.
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The correct answer is C. Dreary.
This is because Le Morte d'Arthur is full of melancholy inducing moments due to the fact that everything will fall apart at a certain point. Arthur's death, and his loss, is inevitable, so is the fall of Camelot, and of his Knights of the Round Table.
The answer is B, as the sentences do not show cause and effect, set up a comparison, or introduce an idea that has already been brought up.
I believe the answer is D. The birth rate in India is greater than in china.
This is because of the "one-child policy" that's enforced in China.