The correct answer is C. For instance.
Step-by-step explanation
A transition is a word or phrase that is used to move from one idea to another. This transition can be used to complement, contrast, deny, and develop an idea. In this case, sentence 3 is a complement to sentence 2 because it provides an example by explaining how some essential items in the library were damaged. So, the most accurate transition for this is "For instance" because it expresses a relation of complement and exemplification. So, the correct answer is C. For instance.