This is tough! However, using a little bit of logic and playing around with formulas, we can solve this!
We know that an inscribed angle = (1/2) intercepted arc. The arc is directly correlated to the area with 16 degrees. Therefore, r=(1/2)(16)=8. An inscribed angle counts as long as its sides intersect the circle to form an intercepted arc, and this is not an option given, so I can understand why you're having trouble. I would recommend asking your teacher about this.
