Why is A not correct?

Just taking a shot here --- I can see why A might be an appealing answer, as I originally selected this one too. However, while Passage A does say that "a certain complexity of sounds can be expected to have a positive effect on the listener," later, the passage says that "sounds that are too complex or disorganized, however, tend to be overwhelming." This forces us to recognize that while some complexity is good, too much is not ideal, therefore, answer choice A is incorrect as it suggests that the more complexity there is, the more a listener will enjoy it, and this isn't true, because only a bit of complexity is ideal.