Grandfather Has a Difficult Time Learning the Names of Some

Multiple Choice

Grandfather has a difficult time learning the names of some new friends that you brought over to meet him. This difficulty is more probably due to

A) his attempts to retrieve the names of other friends he met previously
B) a slow down in the rate at which he can process new information
C) a general decline in his ability to encode information deeply
D) his lack of interest in meeting your new friends