Correct option is: (A) 100°
We know that angle made by an arc at centre is double than the angle made by that arc at any point on the remaining circumference of circle.
\(\because\) \(\angle\) ACB is angle made by arc AB at point of circumference of circle.
& \(\angle\) AOB (or x) is angle made by arc AB at centre of the circle.
\(\therefore\) x = 2 \(\angle\) ACB = 2 x 50° = 100°.