Question

this sign indicates
a winding road ahead.
a right turn ahead.
a double curve ahead.
a curve to the right ahead.

Explanation:

The road sign shown is a warning sign with a single curve (specifically a curve to the right) in the arrow. A "winding road" sign would have multiple curves, a "right turn" is a sharper 90 - degree - like turn, a "double curve" has two curves, and this sign indicates a curve to the right ahead.

Answer:

D. a curve to the right ahead.