Answer:
I really don't know but sorry
I believe it going to be A.
Transitions in a piece of writing help organize the text. Transitions can be found inside a paragraph, between paragraphs or between sections in a long writing.
Some very common transitional expressions can show addition, cause and effect, example, exception, sequence, conclusion or similarity. Using these expressions helps give the text meaning and organization, and they might help if we want to summarize a text.
According to everything explained above, the correct answer would be "C".
