In Sperling's Investigations of Iconic Memory, Subjects in the Partial

In Sperling's investigations of iconic memory, subjects in the partial report condition:

A) were asked to report only a specific portion of the display they had seen
B) heard a tone that signaled which row they should report, just before the display was presented
C) were asked to report as many letters as possible from the display they had seen
D) typically performed much worse than subjects in the whole report condition