What Were the Results of Sperling's Partial-Report Procedure

What were the results of Sperling's partial-report procedure?

A) If a tone was sounded immediately after the matrix disappeared, people accurately reported all letters in the row signaled by the tone.
B) If a tone was sounded immediately after the matrix disappeared, people accurately reported all letters in the top row and part of the second row only.
C) If a tone was sounded 2 seconds after the matrix disappeared, people accurately reported all letters in the row signaled by the tone.
D) If a tone was sounded 2 seconds after the matrix disappeared, people accurately reported all letters in the matrix.