Question

read the passage.
synesthesia: mixed-up senses
we generally think of our senses as having completely separate functions. this is a logical assumption; after all, we cant see with our ears or taste with our eyes. for people with a condition called synesthesia, however, senses can be conflated, or mixed together. in fact, the word synesthesia, derived from greek, literally means \sensations together.\ this combining of senses causes interesting sensory experiences. for example, some synesthetes (people who experience synesthesia) imagine tasting a particular flavor whenever they hear a certain sound. others \hear\ a sound in their minds whenever they touch a certain object. the most common types of synesthesia involve colors. in one common subtype, for instance, synesthetes associate different colors with different letters of the alphabet. typically, synesthetes are not bothered by their synesthesia; in fact, many enjoy it.
what is the main, or central, idea of the passage?
people with synesthesia may hear a sound when they touch an object.
people with synesthesia experience a fusing of different senses.

Explanation:

The passage starts by stating that for people with synesthesia, senses can be conflated. Then it gives examples like tasting a flavor when hearing a sound, "hearing" a sound when touching an object, and associating colors with letters. All these examples support the idea that people with synesthesia experience a fusing of different senses. The first option is just one specific example, while the second option captures the overall concept presented in the passage.

Answer:

People with synesthesia experience a fusing of different senses.