A yellow warning sign with an arrow curving right and then left indicates:

Correct answer: B. – Successive curves, beginning to the right
This warning sign shows that the roadway first curves right and then curves left. Reduce speed before entering the first curve and remain within your lane through both changes in direction. An advisory-speed plaque may be posted below the sign to recommend a safe speed.
Source: Massachusetts Driver’s Manual — Ch. 4, “Warning Signs”


