Which Statement About Sperling's Procedures to Study Sensory Memory Is

Which statement about Sperling's procedures to study sensory memory is correct?

A) On each trial, participants recalled about 4.5 letters in the full-report procedure but all letters in the partial-report procedure.
B) On each trial, participants recalled about 4.5 letters in the partial-report procedure but all letters in the full-report procedure.
C) There was a negative correlation between number of letters recalled and time delay before auditory cue in the partial-report procedure.
D) There was a negative correlation between number of letters recalled and time delay before auditory cue in the full-report procedure.