Correct answer:
"All of these are equally affected."
When in Alzheimer's disease, all of the working memory is in peril. In early stages of Alzheimer's disease, all of these functions start to have problems. Phonological loop is basically the capacity to memorise speech or information in it. Central executive is the ability to switch attention from one activity to another that is needing more attention. The visuospatial sketch pad is the ability to handle visual and spatial information being able to judge distances for example. All of these are part o the working memory and are affected from the early stages of Alzheimer's disease.