The area of the brain that receives information from the nose is directly connected to the limbic system, rather than relayed first through the thalamus. this connection may explain why smells are often involved
a. pain sensations
b. altered states of consciousness
c. subliminal messages
d. vivid memories
e. retinal disparity

The answer is d. vivid memories.

Explanation:

The limbic system, among other things, is responsible for memory and emotions. Since smell is connected to this system, it is a very powerful sense memory-wise.

Another reason the sense of smell is so sensitive is because it has a long evolutive history. Most single-cell organisms rely on smell as a means of interaction, so naturally it has developed in humans and other mammals.