Bob has to have his gall bladder removed. He doesn't know anyone who has had this procedure before, and since a human only has one gall bladder, he personally has never been through this process before, so as he selects a surgeon, he finds the different services difficult to interpret, due to his lack of prior experience, familiarity, and knowledge. This is known as which part of service intangibility within the key service communication challenges? A) incorporeal existence B) abstractness C) generality D) non-search ability E) mental impalpability