Okay, well A and B you can throw out immediately because they don't make sense. Sensory memory is part of short-term memory, not the other way around. Short-term and long-term memory are completely distinct and dissociated. So you're left with either short-term and long-term memory are uniform and similar or they're different. And from the figure, you can see that people tend to remember things from the beginning and end of the list (primacy and recency effects, respectively). One hypothesis for the primacy effect is that people can rehearse items from the beginning of the list because there's no other context and they stand alone. So basically, the primacy effect can be attributed to long-term memory in this hypothesis. Amnesiacs without long-term memory show no primacy effect. So the fact that these people show both primacy and recency (short-term memory) effects shows that they have both and that both are different.
Another, shorter way to look at it is that short- and long-term memories are clearly distinct because the patients remembered things from the beginning and end of the list but not the middle. Or, even simpler, you should know from your P/S studies that short- and long-term memories are different.
