Answer:
Transience.
Explanation:
Transience may be defined as the passing of memory or something with time. The memory are short lived and usually decreases with time. Transience is common with the increasing age.
Amanda tried hard to focus on her psychology professor but her mind wander on other things. She loses the memory of the psychology lecture and completely forgets after sometime. This explains the state of the transience of consciousness.
Thus, the correct answer is option (C).