Which harmony is the most appropriate for the chord in the rectangle?

ANSWER

The chord consists of Bb, Db, Fb and Ab in Ab major key. It connects the secondary diminished chord and its resolution in-between by stepwise motion. The lowered 6th degree scale was used, which is the most typical case of the borrowed chord. Correct answer is 4.
Which harmony is the most appropriate for the chord in the rectangle?
ANSWER
The chord consists of Bb, Db, Fb and Ab in Ab major key. It connects the secondary diminished chord and its resolution in-between by stepwise motion. The lowered 6th degree scale was used, which is the most typical case of the borrowed chord. Correct answer is 4.