A Student Has Taken a Summer Job Answering Telephone Calls

Multiple Choice

A student has taken a summer job answering telephone calls for sales orders.He quickly learns that it is pretty easy to remember a customer's seven-digit phone number,but it is much more difficult to keep track of a sixteen-digit credit card number.According to the conclusions of researcher George Miller,why is the student having difficulty with longer strings of numbers?

A) the capacity of sensory memory is quite limited.
B) memory span covers only five to nine items.
C) retroactive interference has taken place
D) the information has not been transferred to his sensory memory.