Answer: D. 12 units.
Step-by-step explanation: We are given a circle with center at O.
Two chords of the given circle are AN and ML.
Chord ML length is given 12 units.
We also given distances of the chords AN and ML from center O of the circle.
Both of the distances of the chords AN and ML from center O of the circle are equal that is 7.2 units.
Note: Equal length of the chord of a circles are equidistant from the center of the circle.
Therefore, length of both chords would be equal.
Therefore, AN = 12 units.
Correct option is D option : 12 units.