What is a notable characteristic of the Belogradchik Rocks regarding their appearance?

What is a notable characteristic of the Belogradchik Rocks regarding their appearance?

A They resemble a modern sculpture.
B They are entirely grey in colour.
C They change colour depending on the light.

Fact: The Belogradchik Rocks display a variety of colours, shifting from deep red to gold as the light changes. This feature adds to their aesthetic appeal and mystique, truly making them a natural gallery.

Correct Answer: They change colour depending on the light.