Answer:
The correct option is A. The length of chord ST in P is 7 units.
Explanation:
Given information: QR=7, distance between center and QR is 3.2 units and the distance between center and ST is 3.2 units.
If two chords are equidistant from the center of the circle, then the length of both chords are same.
From the given figure it is clear that the two chords QR and ST are equidistant from the center of the circle,so the length of both chords are same.
The length of chord ST in P is 7 units. Therefore the correct option is A.