What may happen if too much black is added to pure yellow?

Correct answer: Yellow may lose brightness and become dark and muddy

Adding black lowers the value of yellow, so its lightness and brightness decrease. When too much black is added, the mixture can look dark, dull or muddy, making the original yellow less clear. Option A is correct. Orange requires red mixed with yellow, while a pale tint requires white; neither result is caused by adding black.