Which sign indicates there is a plate below some signs providing extra information?

Answer: C — Plate below some signs

This tests understanding that some main road signs come with an extra plate fixed below them to give additional details. The sign that indicates there is such a plate is the one described as “Plate below some signs,” because it explicitly tells you there is extra information under the main sign. The other options describe the type of junction or road feature (roundabout, bend ahead junction, crossroads) and do not convey the presence of a supplementary plate. When you see a sign with a smaller plate beneath it, read that plate for the extra details like times, distances, or restrictions.