What does a yield sign mean?

Answer: D — Slow down and stop if necessary

A yield sign indicates that drivers should slow down and stop if necessary to allow other traffic to proceed before moving forward. Option A suggests a sudden stop, but this is not always required. Option B is a close choice, but still not as accurate as the correct answer. Option C suggests that the driver should drive at the posted speed limit, which is not correct as a yield sign requires the driver to slow down. Therefore, the best answer is option D as it encompasses all the necessary actions a driver must take when encountering a yield sign.