Concept:An angle bisector divides an angle into two equal parts.Explanation:From the diagram, OP bisects ∠ROS.So, ∠POS=21×∠ROS.Given ∠ROS=66∘, we get:∠POS=21×66∘=33∘.From the construction lines, ∠POQ=∠POS.Therefore, ∠POQ=33∘.But ∠POQ=3x.Hence, 3x=33∘.Divide both sides by 3:x=333∘=11∘.Answer:x=11∘, which is option B.