Answer:
Limbic System ; Emotion ........ A)
Explanation:
Ok so aparently there seem to be two questions in this statement,
The answer to the first question is that the sense of smell projects directly to the limbic system. The limbic system is a set of structures that are located in the brain and handle everything that relates with emotion and memories. Which is why the smell made Randolf have that memory which then caused an emotional response.
The answer to the second question is that the answer that is not a disadvantage of PET scanning is that an alternative diagnostic tool is fMRI. Mainly because alternatives are always a good thing since they provide validity.