What does a sign featuring two lines curving towards each other indicate?

A sign featuring two lines curving towards each other indicates that the road narrows on both sides. This is a warning sign meant to alert drivers that they need to be cautious as the roadway may become narrower than it currently is, which could pose a hazard if drivers are not prepared to adjust their speed or position on the road. Recognizing these signs helps ensure that vehicles maintain safe spacing and avoid collisions, particularly in areas where larger vehicles might struggle to navigate.

The other options provide different warnings or instructions, such as merging or speed limit changes, but do not accurately describe the intention of the sign in question. Understanding the specific meaning of each road sign is essential for safe driving practices and maintaining traffic flow, particularly in complex road conditions.