George Sperling Conducted a Study in Which He Varied the Interval

George Sperling conducted a study in which he varied the interval between the presentation of a letter matrix and an auditory recall cue. Sperling measured the proportion of letters participants could recall from the matrix. Which of the following statements is FALSE regarding this study

A) A graph of the results of this study would show the accuracy of recall on the y-axis.
B) The interval between the matrix and the cue is a dependent variable.
C) All the letters in the matrix are stored in memory.
D) Sperling's study provided knowledge regarding sensory memory.