Answer:
30°
Step-by-step explanation:
Line AB and BC are tangents to the given circle.
[tex] \angle \: ABC = \frac{1}{2} ( 210 - 150)[/tex]
[tex] \angle \: ABC = \frac{1}{2} (60) = 30 \degree[/tex]
Alternatively, <ABC and <AOC are supplementary because AB and BC are tangents.
[tex] \angle \: ABC + 150 \degree = 180 \degree[/tex]
[tex] \angle \: ABC = 180 \degree - 150 \degree = 30 \degree[/tex]
The correct choice is A.
