Answer:
List A; chunking
Explanation:
Chunking: In psychology, the term chunking was given by George A. Miller in 1956 in one of his papers. It refers to the phenomenon that involves taking specific pieces of a particular information or chunk and then grouping those pieces into big or larger units. By using the process of chunking, an individual tends to connect each piece of information into a large unit and therefore, he or she improves the amount of particular information to be remembered.
In the question above, the participants will recall more letters from list A which can be best explained by the use of chunking.