Answer:
D
Step-by-step explanation:
If AB is a tangent, then angle A must be a right angle.
If angle A is a right angle, then triangle ABC is a right triangle and will work in the Pythagorean theorem formula.
a^2 + b^2 = c^2
8^2 + 16^2 = 20^2
64 + 256 = 400
320 = 400
Since 320 = 400 is false, angle A is not a right angle, and AB is not a tangent to circle C.
Answer: D
