I believe C is correct, after reading through a few times I don't feel as though there is a defined topic sentence. The paragraph just seems to list facts without any true purpose.
Answer:
the Party has altered the records to reflect their version
It is defining.
Defining relative clause does not have a comma, while a non-defining relative clause has.
For example, if the sentence is:
The children, who hate chocolates, are uncommon.
- since there is comma in this sentence, it is non-defining.
- while if there is no comma like the question in the picture, it is defining.
Jim chose Bill and Terry for his team Sandra chose Gina and Mary Luke chose Audrey and Reggie.
