Which harmony is appropriate for the notes in the rectangle?

ANSWER

The chord is a dominant 7th chord consisting of F, A, C and Eb. Since A doesn't belong to the scale and the following chord is the tonic which resolves the dominant 7th, it is the secondary dominant chord. Correct answer is 4.
Which harmony is appropriate for the notes in the rectangle?
ANSWER
The chord is a dominant 7th chord consisting of F, A, C and Eb. Since A doesn't belong to the scale and the following chord is the tonic which resolves the dominant 7th, it is the secondary dominant chord. Correct answer is 4.