f
The text of A is generally correct. Lack of the 
before the 2nd note is however most probably a result of Chopin's distraction (haste). It is revealed by the place before the note, most probably left for the accidental to be inserted and, above all, by a later proofreading of FE (→GE,EE), in which both the and the cancelling it 
before the 8th semiquaver were added. It is not the only omission of an accidental introducing alteration of this kind in Chopin's works, although it rarely occurs (e.g., in the Etude in F minor, Op. 25 No. 2, bar 56).
Compare the passage in the sources »
category imprint: Differences between sources
issues: Omissions to cancel alteration, Errors of A, Authentic corrections of FE
notation: Pitch
