Please help with this

Step-by-step explanation:

Since O is the center of the circle, from that point to any point that lies on the outside of the circle will have the same measure. That's worded weird. From point O to A, which is a radius, the length of that radius is 12. That means that the length from point O to any point on the outside of the circle will also measure 12. So from O to B is also 12. For y, we have a rule for when 2 lines tangent to a circle meet at a single point outside the circle. The 2 tangent lines are equal in length. So that means that if AC is 19.6, the CB is also 19.6. Your answer choice is 4.

a is the right answer