Answer:
Option C. 4 Units
Explanation:
From the intersecting chords theorem we know that if two chords are intersecting each other in a circle then the products of the lengths of the line segments of each chord are equal.
Therefore AY.YC =YB.YD
Here AY = x, BY = 3, YC = 6, YD = 8
So x.6 = 3.8
6x = 24
x = 24/6 = 4 Units
Option C 4 units is the correct option.