Answer:
D. It appears that
Step-by-step explanation:
Option D, "It appears that," is the most appropriate choice to insert at the beginning of sentence 10 because it indicates that the information in the following clause is based on observations or evidence, rather than being a statement of fact. This fits with the context of the sentence, which suggests that the behavior of the jailbreaking rats is being interpreted or inferred based on their actions.
Option A, "It is true that," would not be an appropriate choice because it asserts that the information in the following clause is definitely true, while the context of the sentence suggests that this is not necessarily the case.
Option B, "They point out that," would not be an appropriate choice because there is no mention of any specific group of individuals making a point or drawing attention to the information in the following clause.
Option C, "They claim it is obvious that," would not be an appropriate choice because it implies that there is a group of individuals making a statement about the information in the following clause, and there is no mention of any such group in the context of the sentence.