Which One of the Following Reflects the Typical Duration of Working

Which one of the following reflects the typical duration of working (short-term) memory?

A) Elly spent the summer at his grandmother's house and while he was there he could remember his grandmother's telephone number; now that he is home he doesn't remember the number.
B) Hani looked up the correct spelling of a word, but by the time she found a piece of paper on which to write the word on, she had forgotten how to spell it.
C) Ebony remembers most of the information that she has learned about the play discussed in class this week; however, she remembers very little of what she learned about two weeks ago.
D) At 9:00 a.m., Darrell makes a mental list of the five items he needs to purchase at the grocery store at the end of the day. At noon he checks himself and realizes that he still remembers all five. However, at 3:00 p.m. he discovers that he has forgotten three of the five items.