The secret room code of 12 constellation.

A: C (gold); A (fire); Ding (soil); B (wood)

Analysis: C is raw water and C is gold.

A, c and a are fire.

Ding Fei water, Ding may be wood or earth.

For example, butyl, if butyl is wood, then b is gold; If it is dirt, then B is wood.

Because gold is already C, B can't be gold and D can't be wood.

So Ding is dirt.