Based on the study of Patient H.M., it has been concluded that

a. immediate memories are stored within the hippocampus.
b. the hippocampus is required for retrieval of long-term memories.
c. long-term memories are stored within the hippocampus.
d. the hippocampus converts immediate memories into long-term memories.
e. damage to the hippocampus results in severe retrograde amnesia.

Answer: d. the hippocampus converts immediate memories into long-term memories.