If a shade of orange becomes too black and lifeless, what is the likely cause?

Correct answer: Too much black

The governing concept is controlled value adjustment. Black is used to create a shade, but it has strong visual and pigment power; adding too much can overpower the red-yellow identity of orange, reduce its chroma, and make it look dull or lifeless. A little yellow or a balanced red-yellow mixture does not produce that effect, and a clean palette prevents contamination. Therefore option A is the likely cause.